July 21, 2023

Stem Galls on Goldenrods (and friends): Gnorimoschema Moth Galls

These are my notes on gall-making Gnorimoschema moths in North American north of Mexico. Much of this is simply a summary from William E. Miller's A Comparative Taxonomic-Natural History Study of Eight Nearctic Gnorimoschema that Induce Stem Galls on Asteraceae, Including Descriptions of Three New Species (Lepidoptera: Gelechiidae) (2000). Miller studied these galls over the course of several decades. In his monograph, he emphasized the importance of physical characteristics of gall construction, particularly the architecture of their exit-holes, for taxonomic differentiation. He also described the biology of several species in detail, performed several interesting experiments in host-choice and gall construction, and directly observed larval behavior during gall exit construction. Unreferenced table entries are from Miller (2000). Name spellings and acceptance follow those in the checklist by Lee et al. (2009), with exceptions indicated.

Gnorimoschema galls versus other goldenrod stem galls

Gnorimoschema is one of several insect groups that can induce stem-swelling galls on goldenrods. Others include Eurosta solidaginis, a tephritid fly that induces the commonly-observed "ball gall". Its galls are nearly spherical, even during enlargement, unlike Gnorimoschema galls, which range in shape from vertically-symmetric ellipsoids to pyriform (exaggeratedly pear-shaped) swellings. Other groups include (1) gall-midges, which usually induce smaller galls, typically with knobby extrusions, usually not horizontally-symmetric, and (2) Epiblema moths, whose stem-boring larvae induce "galls" that are basically rudimentary swellings - usually with buckling, vertical scars on the outside. These occur high on the stem and are typically accompanied by much plant branching. In the instances where they are noticeably vertically asymmetric, the narrower section usually points down. In contrast, Gnorimoschema gall exteriors are similar in texture to the surrounding stem tissue, and if vertically asymmetric, the narrower section points up.


(At least for the first ten entries - mostly eastern taxa) Gnorimoschema larvae usually enter the host plant stems at the apex of an elongating shoot. They tunnel down a few centimeters, boring through pith, then reverse direction and initiate a gall a few cm above their lowest tunnel. Larval entry usually deforms the leaves at the terminal bud into characteristic shapes, so, at least for most species, the presence of a larva may be discerned before it begins to induce its gall. The larva pre-bores its (eventual) exit hole prior to pupating. It excavates a tunnel out of the gall cavity, usually somewhere in the upper third of the gall (but see G. gallaespeciosum) to the outside, but stops just before breaking the plant epidermis. Some exits remain capped with this thin remnant of stem epidermis and the larva's exit construction is complete. In other species, the larva additionally constructs a "bung" - a stopper-shaped object that seals the gall exit hole from the outside. After the bung is complete, the epidermal covering sloughs off, exposing the outer surface of the bung to the outside world. Its geometry means that it can be pushed out easily from within by the emerging adult moth, but cannot be pushed-in. Bungs were initially thought to be composed of aggregated silk, but in most species they are actually composed of combination of silk and a hardening larval exudate, perhaps ultimately derived from plant resins (Miller 2000).

Gnorimoschema gallaesolidaginis larvae are one of few lepidopterans that are able to feed on plants without inducing the host's jasmonate signaling response (Tooker et al. 2008). Fascinatingly, they are able to suppress this host defense system while simultaneously inducing the host to increase production of nutritive lipids, including the very lipids that are biosynthetic precursors of jasmonic acid (Tooker & De Moraes 2009). Wow! They still manage to get parasitized, though.

Gnorimoschema species and their galls

moth host gall location gall form exit hole notes
Gnorimoschema gallaesolidaginis Solidago altissima stem, about mid-height and lower hard ellipsoid spindle upper third

flush white bung
Host-mismatches on S. gigantea are suspected but are extremely rare (Nason et al. 2002; Miller 2000). Mismatches may be detectable by the nature of the exit hole: When third-instars were experimentally transferred from their original galls to empty galls on S. gigantea they still produced white bungs in their new home (Miller 2000). There are also doubtful records from S. missouriensis and S. nemoralis. Miller did not differentiate between S. canadensis and S. altissima; it is possible that this and other members of Solidago ser. Canadense may also serve as hosts.
Gnorimoschema jocelynae Solidago gigantea, S. ulmifolia?, S. rugosa?? stem, about mid-height and lower hard ellipsoid spindle upper third

recessed brown bung
Host-mismatches on S. altissima are suspected but are extremely rare (Nason et al. 2002; Miller 2000). Mismatches may be detectable by the nature of the exit hole: When third-instars were experimentally transferred from their original galls to empty galls on S. altissima they still produced dark bungs in their new home. S. ulmifolia may serve as an occasional host (Miller 2000). Miller almost never mentions the ubiquitous S. rugosa, which is similar to S. ulmifolia. I think it's likely that at least some of his records from S. ulmifolia actually refer to this host species. Nason et al. found strong evidence for host-associated genetic differentiation, but were somewhat equivocal as to whether the genetic distance was enough to qualify S. gigantea-raised moths as a distinct species from G. gallaesolidaginis, rather than a host-race or semispecies. The adults are nearly identical. Lee et al. (2009) recognize this species.
Gnorimoschema salinaris Solidago sempervirens, S. juncea, , S. ulmifolia?, S. rugosa?? lower stem, near ground hard ellipsoid or pyriform spindle upper third

flush brown bung with interior white cushion

(but see notes)
Classically known from S. sempervirens only, Miller assigned galls and adults reared from galls on S. juncea to this species. The entry in this table reflects his observations. He also reports that it may occasionally form galls on S. ulmifolia. Miller almost never mentions the ubiquitous S. rugosa, which is similar to S. ulmifolia. I think it's likely that at least some of his records from S. ulmifolia actually refer to this host species.

I do wonder whether his inland galls on S. juncea are truly conspecific with G. salinaris; one photo of a gall on S. sempervirens shows a light-capped exit hole rather than a brown-capped one (Patterson 1915). S. juncea and S. sempervirens were once thought to be closely related; they are now in different sections (Semple & Beck 2021).

I think it is likely that members of Solidago sect. Maritimae other than S. sempervirens may also serve as hosts, particularly the barely-distinct S. mexicana. Miller performed gall-transplant experiments with S. juncea-raised larvae. When moved into emptied galls on S. altissima they still produced their characteristic dark bungs with white cushions, the bung exterior surface flush with the surrounding plant epidermis.
Gnorimoschema septentrionella Symphyotrichum novi-belgii, S. pilosum, S. lanceolatum stem, mid-height or sometimes quite high hard ellipsoid or pyriform spindle upper third

no bung

exit difficult to discern
Fyles (1911) reared the type specimen from "Aster junceus Ait.", which POWO lists under S. novi-belgii, but this may also have referred to what is now S. boreale; I'm not sure. Miller reports it from many other asters, all of which are now in the genus Symphyotrichum. This includes S. praealtum, but this is probably a misidentification because this collection is from Upper Michigan, outside the range of S. praealtum. In my experience S. praealtum is very difficult to distinguish from the widespread and polymorphic S. lanceolatum.
Gnorimoschema gallaespeciosum Solidago rigidiuscula very low on stem hard ellipsoid spindle middle third

no bung
Miller described and reared this species from "Solidago speciosa" in Minnesota; based on his site description this was probably the newly-resegregated S. rigidiuscula, but it is conceivable that other Solidago species in subsection Erectae could also serve as hosts, including S. speciosa in the strict sense.
Gnorimoschema gibsoniella Solidago rigida, Symphyotrichum pilosum very low on stem hard ellipsoid or pyriform spindle upper third

no bung
The type specimen was reportedly reared from Solidago rigida in Manitoba, but Miller was unable to find any Gnorimoschema galls on that species, despite searching extensively near the type locality (and elsewhere in the upper Midwest). He did rear adults from galls on "Aster spp." (elsewhere he specifies mostly "Aster pilosus") that he identified as G. gibsoniella. He reports this gall from MD, IL, MN, and MI. Solidago rigida does not resemble Symphyotrichum pilosum. I find it hard to believe that anybody would mistake the two, even without flowers present. Maybe this species is a prairie-Astereae oligotroph?
Gnorimoschema busckiella Symphyotrichum patens lateral stems spindle?

no bung
Known only from the type series - NJ.
Gnorimoschema subterraneum Symphyotrichum ericoides, S. chilense ground-level on stem spindle? Type from "Aster multiflorus" - this may actually refer to another Symphyotrichum species; Miller assigned it to S. ericoides. Powell & Povolný (2000) ascribed moth galls on S. chilense to this species in West.
Gnorimoschema gallaeasterella Solidago flexicaulis, S. caesia, S. uliginosa, Eurybia divaricata, Symphyotrichum cordifolium near apex of stunted stems hard ellipsoid spindle conflicting descriptions This one is a confusing mess. Kellicott's original description (1878) gave E. divaricata as the host, but the accompanying illustration looks more like Solidago flexicaulis, as pointed out by Brodie (1909a). Brodie found many galls similar to the illustration on S. flexicaulis, as well as some on the related S. caesia (1909b). He was able to rear adults only from S. flexicaulis, which he identified with Kellicott's description of adult G. gallaeasterella. He also reported that these galls were being harvested en masse as a quack medicine, branded "Fitt Apples", by an enterprising local crank. He gave a provisional name, ceasiella, for the S. caesia-derived galls in case those would prove to be the work of a distinct species. Busck determined that moths reared from both S. flexicaulis and S. caesia galls were in fact G. gallaeasterella (Cosens 1910). He also assigned somewhat different-appearing moths reared from Doellingeria umbellata to this species (1939, and in earlier works), in disagreement with their discoverer, Fyles (1890, 1911), who considered these a distinct species (see next). Busck still maintained that moths reared from Eurybia divaricata were also this species. Miller found a few galls on Symphyotrichum cordifolium, and used these, as well as older descriptions, as the basis for his description. He did not rear any moths of this species, however. He described them as lacking bungs, but earlier descriptions (on other hosts!) do specify a "plug" (color not given) capping the exit hole (Kellicott 1878). McDunnough (1959) compared moths from galls on stems of Doellingeria umbellata against those raised from galls stunting Solidago uliginosa nearby. He concluded that they were definitely distinct, with obviously different female genitalia. He confidently identified the S. uliginosa-derived moths as G. gallaeasterella, despite this being a new host, based on the stem-stunting position of the gall and apparently all aspects of the adult moth appearance.
Gnorimoschema gallaediplopappi Doellingeria umbellata mid to lower stem hard ellipsoid spindle upper third

no bung
See previous; while Lee et al. (2009) still reject this species, every author (other than Busck) who has published on it seems to have recognized it as distinct. Miller (2000) provisionally accepted it, having neither personally observed nor collected it. McDunnough (1959) reared it from Doellingeria and emphasized the adults' morphological distinction from G. gallaeasterella. He also reported galls on Solidago rugosa in Nova Scotia that produced an unidentified Gnorimoschema male very similar to this species. Table entries from description in Fyles (1911), not Miller as in other entries.
Gnorimoschema slabaughi Grindelia squarrosa main and lateral stems hard ellipsoid spindle upper third

bung of coarse plant fragments and silk
Gnorimoschema baccharisella Baccharis pilularis twigs spindle open when mature
(larvae exit gall to pupate)
Gnorimoschema grindeliae Grindelia hirsutula soft, nonpersistent swelling open when mature
(larvae exit gall to pupate)
Gnorimoschema crypticum Hazardia squarrosa, Isocoma menziesii soft, nonpersistent swelling open when mature
(larvae exit gall to pupate)
Gnorimoschema octomaculella Acamptopappus sphaerocephalus, Chrysothamnus spp. leaves open when mature
(larvae exit gall to pupate)
Gnorimoschema coquillettella Acamptopappus sphaerocephalus, Ericameria arborescens, E. linearifolia leaves onion-shaped structures from sealed-together leaflets (larvae exit gall to pupate)
Gnorimoschema ericameriae Ericameria ericoides leaves onion-shaped structures from sealed-together leaflets (larvae exit gall to pupate)
Gnorimoschema powelli Baccharis sarothroides stems swellings


  • Brodie, W. Lepidopterous galls collected in the vicinity of Toronto — No. 2. The Canadian Entomologist 41, 73–76 (1909).
  • Brodie, W. Galls found in the vicinity of Toronto — No. 3. The Canadian Entomologist 41, 157–160 (1909).
  • Busck, A. Restriction of the genus Gelechia (Lepidoptera: Gelechiidae), with descriptions of new genera. Proceedings of the United States National Museum 86, 563–593 (1939).
  • Cosens, A. Lepidopterous galls on species of Solidago. The Canadian Entomologist 42, 371–372 (1910).
  • Fyles, T. W. Gelechia gallaediplopappi (n. sp.). The Canadian Entomologist 22, 248 (1890).
  • Fyles, T. W. Gnorimoschema gallaediplopappi Fyles and Gnorimoschema gallaeasterella Kellicott. The Canadian Entomologist 43, 135–137 (1911).
  • Kellicott, D. S. A new gall moth, and notes on larvae of other gall moths. The Canadian Entomologist 10, 201–205 (1878).
  • Lee, S., Hodges, R. W. & Brown, R. L. Checklist of Gelechiidae (Lepidoptera) in America North of Mexico. Zootaxa 2231, 1–39 (2009).
  • McDunnough, J. H. On some changes in nomenclature of microlepidoptera, with description of a new species. American Museum Novitates 1–9 (1959).
  • Miller, W. E. A comparative taxonomic-natural history study of eight Nearctic species of Gnorimoschema that induce stem galls on Asteraceae, including descriptions of three new species (Lepidoptera: Gelechiidae). (Entomological Society of America, 2000).
  • Nason, J. D., Heard, S. B. & Williams, F. R. Host‐associated genetic differentiation in the goldenrod elliptical-gall moth Gnorimoschema gallaesolidaginis (Lepidoptera; Gelechiidae). Evolution 56, 1475–1488 (2002).
  • Patterson, J. T. Observations on the development of Copidosoma gelechiae. The Biological Bulletin 29, 334–372 (1915).
  • Semple, J. C. & Beck, J. B. Revised infrageneric classification of Solidago (Asteraceae: Astereae). Phytoneuron 2021–10, 1–6 (2021).
  • Tooker, J. F., Rohr, J. R., Abrahamson, W. G. & De Moraes, C. M. Gall insects can avoid and alter indirect plant defenses. New Phytologist 178, 657–671 (2008).
  • Tooker, J. F. & De Moraes, C. M. A Gall-inducing caterpillar species increases essential fatty acid content of its host plant without concomitant increases in phytohormone levels. Molecular Plant-Microbe Interactions 22, 551–559 (2009).
Posted on July 21, 2023 07:26 PM by ddennism ddennism | 1 comment | Leave a comment

August 11, 2022

Goldenrod Leaf Bunch Galls

Here is a pictorial identification guide with some quick distinguishing characteristics.

They're not all caused by Rhopalomyia soldiaginis, despite what the iNaturalist computer vision sometimes suggests. Galls early in development can be tough to identify from photos with confidence. Some of these species have infrequently-observed spring-season galls, which are not described here.

"Leaf bunch" here refers to galls composed of leaves clustered together on a goldenrod shoot. Because the modified structure is usually derived from a bud it also makes sense to call these "bud galls". Please see my catalog of gall-formers on goldenrods for references, more information, and other types of galls on goldenrods.

This covers most of eastern North America north of Mexico, with the caveat that most of the literature on these organisms is focused on the Mid-Atlantic USA. Southeastern states, for example, may have other, undescribed species. Regional biases could also affect the host-mapping given here. Eurosta solidaginis, the goldenrod ball-gall fly, jumps hosts across its large geographic range; maybe some of these flies do that, too.

On Solidago species (true goldenrods)

Rhopalomyia solidaginis

A gall-midge. Induces tufted mopheads of leaves at the shoot apices of several goldenrod species, including the most common species in eastern North America - Solidago altissima. S. altissima is often the dominant goldenrod species in old-fields, meadows, etc. It is likely the species that comes to mind when you hear the word "goldenrod", especially if you're from eastern North America. This midge also hits Solidago canadensis and Solidago rugosa, which are common species that occur in the same places as S. altissima. All three host species have hairy stems - but check this at mid-plant height, not among the flowering branches - and by summer they have dropped their basal leaves. The gall's leaves are messy at first glance, but actually organized into one or a few distinct rosettes, each rosette with leaves getting progressively thinner toward the center. The innermost leaves are nearly linear. The insect chambers are hidden from view, in the very center of each rosette. They are perched above the stem, not hollowed out within it. These chambers take the form of soft-walled, white, translucent cones. Note: This midge has also been reared from similar galls on Solidago rugosa (see plant ID hints under Asphondylia rosulata below), but a recent record of Rhopalomyia capitata from Solidago rugosa makes me think that R. solidaginis leaf-bunching galls on S. rugosa probably shouldn't be ID'd to species without rearing.
R. solidaginis multiple rosettes example R. solidaginis vertical section R. solidaginis single rosette example

Rhopalomyia capitata

This is another gall midge that makes mopheads at the top of goldenrod shoots. It is similar to R. solidaginis, but uses a different host - Solidago gigantea. Like the hosts of R. solidaginis, this host is another tall goldenrod species that produces pyramids of yellow flowers. It generally prefers wetter places than the hosts of R. solidaginis, but it can also be found growing next to them. S. gigantea, unlike the hosts of R. solidaginis, has smooth stems at mid-stem height. It also has distinctly fatter flower-heads, overstuffed with disc florets. You can usually find at least some flower heads with over ten disc florets - this is very rare in the hosts of R. solidaginis, which typically max out around six. The gall itself has leaves that are typically not organized into discernible rosettes, instead resembling a putting green of leaves of even, short length. These are surrounded by a few wide leaves that sheath the overall structure. There can be many insect chambers distributed haphazardly among the short leaves. In cases where there are fewer insect chambers than is typical, the gall can look less like a putting green and more like a disorganized mess. The insect chambers are soft-walled, white, translucent cones, very similar to those of R. solidaginis. As with R. solidaginis, they are not visible until the surrounding leaves are removed. Note: Rhopalomyia capitata has recently been reported from the hairy-stemmed S. rugosa by Charley Eiseman, where it made single-chambered R. solidaginis-like galls. The host specificities of R. solidaginis and R. capitata may therefore not be as absolute as this guide presents, particularly on atypical hosts like S. rugosa, but they do appear to be very strongly specialized nonetheless.

R. capitata typical gall R. capitata peeled R. capitata versus R. solidaginis

Procecidochares atra

Unlike the others on this list, these galls are not the work of a gall-midge. P. atra is a Tephritid fly (one of two groups of flies known as "fruit flies"). This fly modifies the growth of either an apical bud (that is, at the tip of the main goldenrod shoot), a cluster of side-buds off the main stem, or both. Each developing fly is contained by a solid mass of highly modified leaves. The bases of the modified leaves form a thick-walled cup- or vase-like structure around a hollow central cavity. This cavity is the insect chamber. It is usually much larger than the inhabitant, a stout larva or an ellipsoid pupa. The leaves that form the cup eventually separate at their tips, but initially appear shingled together like an artichoke or a Brussels sprout. As the gall grows, the leaf tips grow also, eventually recurving and splaying outwards, giving the appearance of a rosette. At this stage, especially on a terminal bud, the galls can have a superficial resemblance to Rhopalomyia solidaginis galls. However, P. atra galls have leaves that do not get very thin towards the center, and there is usually a semi-open cavity visible at the center. When multiple rosettes are present, only one (if any) is ever attached to the very apex of the stem, pointing upwards. The others are attached below, and point outwards. When a terminal bud gall is present, it is often much larger than the accompanying side-bud rosettes. The host range of this species is not well-characterized, but it appears to include many goldenrods along with other aster family members. There may be multiple cryptic species within "P. atra".
P. atra axial bud galls P. atra apical bud gall with axial galls clustered below
P. atra apical bud gall vertical section P. atra lone apical bud gall P. atra developing axial bud galls P. atra galls on Solidago bicolor

Asphondylia monacha

This midge forms prominent spherical complexes made of several mini-rosettes at the apex of a shoot. This gives galled plants the overall appearance of a shaggy lollipop. It primarily hits Solidago juncea - "early goldenrod" - a host species whose largest leaves are the lowest on the stem and whose stems are strictly hairless (sometimes there are a few hairs among the flowering branches, but often these are smooth as well). It has a preference for drier or rockier sites than the hosts above, but can also be found among them. At the center of each mini-rosette within the gall is an insect chamber that is a stiff, hard-walled, greenish cone made of about two modified leaves, stuck together as if by dried glue. They are not always visible without peeling away the surrounding leaves. The insect chambers have a white fungus lining the walls. Occasionally, the mini-rosettes are not organized into a spherical complex, but instead are distributed along the stem, clustered where stem-leaves attach, or dispersed among the flowering branches. A. monacha can hit a number of other host species, including Solidago erecta and Solidago uliginosa, and probably others.
A. monacha typical gall cluster A. monacha mini-rosette and insect chamber A. monacha dispersed rosettes

Asphondylia solidaginis

This midge makes two types of galls. The first are "leaf-snaps" on Solidago altissima and other goldenrods with hairy stems and narrow "triple-veined" leaves. Leaf-snaps are leaf blisters that connect two leaf blades together, forming a round, hard compartment that contains the insect. These are conspicuous and are often posted to iNaturalist. Bud galls, the second type of gall produced by A. solidaginis, are less frequently noticed. These galls are much smaller than those made by R. solidaginis. They always occur as a single rosette, with leaves that get shorter, but not much narrower, toward the center. As with several other Asphondylia bud galls, the insect chamber is a stout, stiff, hard-walled, greenish cone made of about two modified leaves, stuck together as if by dried glue. The inner walls are lined by white fungal tissue. The insect chamber is prominently visible in the center of each rosette without peeling away the surrounding leaves.
A. solidaginis typical bud gall among flowering buds A. solidaginis typical apical bud gall A. solidaginis leaf-snap galls and apical bud galls

Asphondylia rosulata

Similar to A. solidaginis in that this species also makes both leaf-snaps and bud galls, but on a different host, Solidago rugosa, which has very hairy stems and net-veined leaves. From above, the veins often appear sunken compared to the surrounding leaf tissue. Unlike the hosts of A. solidaginis, you cannot make out three unambiguous "main veins"; instead the veins branch away from the midrib in the familiar way of most leaves, with successive side-veins getting progressively smaller towards the leaf apex. The gall's insect chambers are similar to those of A. solidaginis. There tends to be less of a distinction between leaf-snap galls and bud galls in this species; some leaf-snap galls appear to arrest shoot growth (see third photo) in the same manner as an apical bud gall.
A. rosulata apical bud gall with few surrounding leaves A. rosulata apical bud gall with a rosette of surrounding leaves A. rosulata leaf-snap gall terminating a shoot

Asphondylia silva

Similar to A. solidaginis bud galls, but hits the distinctive host, Solidago caesia. This host is a woodland goldenrod species with arching stems. Its flowers are distributed along the stem at the points of leaf attachment, rather than in a pyramidal cluster at the end of the stem. The gall is not conspicuous, and sometimes appears only as a bare insect chamber accompanied by a few shortened leaves. I have found some apical bud galls on S. caesia in northern Michigan that have a more elaborate rosette of surrounding leaves. Otherwise similar to the bud galls of A. solidaginis.
A. silva apical bud gall from the Type specimen locale A. silva-like apical bud gall with a rosette of surrounding leaves A. silva-like apical bud gall lacking surrounding rosette

Asphondylia pumila

Similar to A. monacha, but occurring on Solidago patula, the swamp goldenrod- an angular-stemmed host with wide, sharkskin-rough leaves that likes wet soil. In the few examples of Asphondylia galls on S. patula that I have seen, the mini-rosettes comprising the galls didn't form the large spherical complexes characteristic of A. monacha, but instead occurred in smaller clusters, flatly terminating the shoot.

Unnamed Asphondylia species

Other Asphondylia-like galls have been reported from Solidago sempervirens, Solidago odora, Solidago nemoralis, Solidago rigida, and probably several others. Some may be caused by A. monacha, others may be the result of distinct species. All have fungus-lined inner insect chambers at the center of rosettes of modified leaves that do not become linear-thin towards the center. Charley Eiseman has a fascinating entry on the S. sempervirens-galling midges here.

Rhopalomyia hirtipes

Narrow leaves surround a prominent, potato-like structure. Usually low to the ground. Found on Solidago juncea, but the host is so drastically modified that it's often tough to identify. The "potato" splits open with four slits at gall maturity, exposing a mass of spongy tissue within from which the flies issue. Included here for completeness, given the cluster of surrounding leaves, but the central globular mass makes these unlikely to be confused with other galls.

Dasineura folliculi

This gall-midge makes clusters of deformed leaves at the shoot apex, each organized into a single rosette. Often, several side-shoots are also galled, perhaps by successive generations of midges. The leaves comprising the gall are wrinkled and blistered. Those toward the center are held tightly together, at least at their bases. There are no insect chambers per se - the larvae instead hide among the wrinkles and crinkles and move about freely, feeding at various spots on and around the gall. These feeding spots appear as pale, circular deformations on nearby leaves. The interior of the rosette contains the stunted bud, often rotting away. Sometimes, however, the bud recovers and continues to grow beyond the gall. The Dasineura larvae that induce the gall are orange. Sometimes there are other Cecidomyiid larval residents. Unlike all the above species, the larvae do not pupate in the gall, instead traveling to the soil to do so. Their pupae will not be found among the gall leaves. Published hosts include the familiar species Solidago rugosa and Solidago gigantea, both with flowers arranged in loose pyramids and basal leaves withered by flowering-time. I have personally found D. folliculi-like galls on S. canadensis and S. caesia; there may be other hosts. Not often found, in my experience, on the ubiquitous Solidago altissima.
D. folliculi gall on S. gigantea with many feeding spots on surrounding leaves D. folliculi gall developing on S. gigantea D. folliculi gall on Solidago rugosa

Various Leaf-Tying Arthropods

The larvae of several moths tie and roll goldenrod leaves together, sometimes very conspicuously, involving many leaves. These structures are not galls, however, because the plant does not participate in their formation. One common genus that does this is Dichomeris, but there are several others. Other arthropods may also form similar structures.
caterpillar leaf-tie on Solidago

On Euthamia ("grass-leaved goldenrods", or "goldentops")

These plants are not particularly close relatives to true goldenrods in the genus Solidago, but they are included here because they were historically placed in Solidago, and often inhabit similar sites. Distinguish them from Solidago by their grass-like, linearly-thin leaves with three to five strictly parallel main veins. Their flowers are organized into flattish structures, all held at about the same level, not in pyramids, fountains, or wands. No basal leaves remain at flowering time, unlike in the Solidago species with flat-topped arrangements of flowers.

Rhopalomyia lobata

These rosette galls have white material in the center that eventually opens to reveal clusters of spongy hairs from which flies emerge. Surrounding leaves have very wide bases that narrow abruptly to resume their normal, grass-like shape. There are often irregular bulges and blisters.
R. lobata gall, opening to reveal spongy white internal tissue R. lobata gall, developing with abruptly narrowing leaves R. lobata gall next to A. pseudorosa gall

Asphondylia pseudorosa

Rosette bud galls, often on side-shoots. Leaves are wider than normal at the base, but taper gradually towards the tip. At the center of the gall is a single greenish, conical insect chamber, typical of the other Asphondylia chambers described above. Early in development the galls do resemble little, green roses. Remnants of old galls dot host plants at the end of the growing season, their wide leaves persisting at nodes created by the growth of axial shoots.
A. pseudorosa gall with typical rosebud form A. pseudorosa bud gall terminating a side-shoot A. pseudorosa gall remnant

Dasineura carbonaria

This gall-midge makes clusters of deformed leaves at the shoot apex, each organized into a single, appressed cluster. The leaves comprising the gall are wrinkled and blistered, often with starkly discolored, purple blisters. There are no insect chambers per se - the larvae instead hide among the wrinkles and crinkles and move about freely, feeding at various spots on and around the gall. The Dasineura larvae that induce the gall are orange. Sometimes there are other Cecidomyiid larval residents.

all images by Daniel McClosky, CC-BY 4.0 (please use with attribution)
suggestions, corrections, comments welcome
Posted on August 11, 2022 06:55 PM by ddennism ddennism | 8 comments | Leave a comment

January 13, 2020

How many cultivated plants are marked as such on iNaturalist?

Thought I'd try to address this question with a semi-scientific approach:

For the past year (1/12/2020 - 1/12/2019) in a 25 square-mile square centered on Blacksburg, VA:

To the best of my ability to determine, there have been:

131 certainly cultivated, marked wild (plants in orderly rows in flower beds, landscape plantings, hanging baskets, houseplants, exotic trees not known to spread from cultivation, etc.)
90 probably cultivated, marked wild (mostly street trees and commonly cultivated plants that could conceivably be escapes or otherwise wild, but are almost certainly planted, just lacking in enough photo context clues to be certain)
1150 probably wild, marked wild (when in doubt, or totally confused, I chose this category)
131 certainly cultivated, marked cultivated
5 probably wild, marked casual (for some reason other than "captive/cultivated")
2 probably wild, marked cultivated (both were chickory, which were growing as weeds in a lawn)

...so for 1509 tracheophytes in the Blacksburg area:

76%-83% observations were of wild plants;
17%-23% observations were of cultivated plants;

of the cultivated plants:
37% were definitely incorrectly marked as wild;
62% were likely incorrectly marked as wild.
37% were definitely correctly marked as wild.

Posted on January 13, 2020 02:09 AM by ddennism ddennism | 4 comments | Leave a comment

October 08, 2019

Goldenrod Galls

Solidago and Euthamia are two plant genera commonly called goldenrods. They host a number of gall-making insects.

This is an attempt to catalog all the gall-making insects on goldenrods. This is probably never going to be a complete list, but I'm striving to include as many as I can find. I'm defining "gall" as a structure primarily composed of plant tissue that is induced by a resident insect and is not otherwise produced by the plant. This definition is a little wishy-washy, and could include other stem-borers and leafminers, for example, but I have excluded those creatures for now. This is not an identification guide for all insect residents of goldenrod galls. In fact, often the current residents of a gall are not the original gall-makers! In some galls, parasitoids and inquilines are more commonly reared than the initial gall-maker.

This entry was motivated by my observation in summer 2019 that many identifications of Rhopalomyia solidaginis summer galls were misidentified on iNaturalist. I think the computer vision algorithm was partly to blame for this; it was aggressively suggesting R. solidaginis as an identification for diverse input images. These included images of other galls, but even extended to images of normal plant structures, especially rosettes of leaves, with no evidence of an insect present. Users also may have been unaware of the great diversity of gall-midges and other gall-makers on goldenrods, selecting R. solidaginis by default for any leafy gall.

Several iNaturalist observations of galls on Solidago and Euthamia don't seem to match those of any known species of gall-maker. There may be quite a few out there to be discovered.

Much of the information on this page comes from the published work of Netta Dorchin and coworkers (see full reference list at end).

Related Resources

Quick guide to identifying leaf-bunching galls on goldenrods:

Quick guide to identifying stem-swelling galls on goldenrods:

Beatriz Moisset's bugguide page on goldenrod galls:

Emily S. Damstra's beautiful scientific illustrations of goldenrods and their associated insects:

Warren Abrahamson's website at Bucknell University reviews his lab's comprehensive research on the evolutionary dynamics of the Eurosta solidaginis system, including a particularly useful goldenrod identification chart for the mid-Atlantic area:

Charley Eiseman's BugTracks blog entries about goldenrod galls:

gallformers.org entries for galls on Solidago and Euthamia:

Catalog of Goldenrod Galls

() = uncertainty in the literature about whether this is a host species, or a note that it more rarely, conditionally, or "accidentally" serves as a host, or a species name included to account for a taxonomic change
(()) = host not mentioned in the literature, but I suspect there might be some observations of this species serving as a host on the internet.

insect host description and notes representative images sources
galls on Euthamia:
Asphondylia Larvae of this gall midge genus develop in chambers composed of modified plant tissue with an inner fungal lining. For several species the walls of the chambers are made of leaf tissue that has the appearance of being glued together, forming either a rigid cone at the site of a bud or a "spot-welded" blister between two leaves. Others develop within modified flower-heads. There are often several generations per year. The organ and host species may vary through the year. Dorchin et al. (2015)
A. pseudorosa E. graminifolia,
((E. caroliniana)),
((E. leptocephala))
Several different gall types per year, always on Euthamia. The most apparent are the bud-rosette galls formed usually on apical buds. These feature a single rosette with broadened outer leaves surrounding appressed inner leaves, the innermost much shorter, forming a single, rigid cone. This conical insect chamber is lined with white mycelium. After the insect leaves or dies the innermost leaves turn black and wither, leaving only the outer, broadened rosette leaves. Before this happens, the gall resembles a green rose flower. Unlike in R. lobata galls, also found on Euthamia buds, spongy white tissue does not form, and each bud gall contains only one inner larval chamber. A second gall type forms later in the season in developing flower head (capitulum) buds. These are difficult to distinguish from normally developing capitula, though they do not flower, and instead house the developing larva. These are also lined with white mycelium. A third type, leaf-snap galls, are pictured in Dorchin et al. (2015) but not mentioned in the text. They appear to be formed near the terminal bud, and are presumably also lined with fungus. Felt (1907) raised Camptoneuromyia flavescens, another cecidomyiid, probably from these galls - specifically the flower-head type. He attributed these galls to "Asphondylia monacha", which is a name he used to refer to what are now known as several distinct Asphondylia species. photo of Asphondylia pseurorosa gall on Euthamia lateral shoot
photo by Brad Walker
(CC BY-NC 4.0) photo of Asphondylia pseurorosa gall on Euthamia terminal shoot
photo by Daniel McClosky
(CC BY 4.0)
Dorchin et al. (2015)
Asteromyia Larvae of this gall midge genus usually develop in flat blisters between the faces of a single leaf. The galls are composed of discolored plant tissue with a brittle inner fungal lining. There are often several generations per year.
A. euthamiae Euthamia sp. leaf spot
(stem spot)
Black blisters on leaves (less-frequently on stems). The blisters are lined with white mycelium. There are several generations per year. Photo of Asteromyia euthamiae galls on Euthamia leaves
photo by cassi saari
(CC BY-NC 4.0)
Photo (2) of Asteromyia euthamiae galls on Euthamia leaves
photo by Sequoia Janirella Wrens
(CC BY-NC 4.0)
Stireman et al. (2010)
Dasineura This large genus of gall midges includes species with diverse life histories and gall forms. The species known from North American goldenrods make deformed and swollen terminal shoot buds with clustered and blistered leaves. The orange larvae develop between the leaves, but exit the gall and pupate in the soil. The shoot sometimes recovers and grows beyond the gall, leaving a deformed section of stem with very short internodes.
D. carbonaria E. graminifolia bud Shoot tip bud galls, formed by several adherent and contorted leaves. Circular discolored feeding spots are often visible, and these may also contribute bumps and wrinkles to the gall. The gall itself is green to purple in color. The galls are not sealed; the larvae freely come and go to feed on the leaves, finally exiting to the soil to pupate.
The name "carbonaria" implies a blackened structure, but this is misleading. This midge species has this name because it was mistakenly assigned to the galls made by Asteromyia carbonifera, which are frequently blackened.
Photo of a D. carbonaria gall on the terminal bud of Euthamia
photo by Michael K. Oliver
(CC BY-NC 4.0)
Photo (2) of a D. carbonaria gall on the terminal bud of Euthamia
photo by Jeff Skrentny
(CC BY-NC 4.0)
Dorchin et al. (2007),
Dorchin et al. (2009b)
Epiblema Larvae of this moth genus (at least those that form goldenrod galls) bore into stems, where they initiate narrow swellings.
E. desertana E. graminifolia stem Very narrow stem swellings. Larvae overwinter in the gall. photo of Epiblema desertana gall on Euthamia
photo by Daniel McClosky
(CC BY 4.0)
See also Miller (1963) for reference photo (pg. 67, Fig. 3d)
Miller (1963)
Miller (1976)
Lasioptera Members of this gall midge genus have a variety of life histories, but most form stem galls. Gagné & Jaschhof (2017)
L. cylindrigallae E. graminifolia stem narrow stem swellings Gagné & Jaschhof (2017)
Galeopsomyia in Eulophidae, a family of chalcidoid wasps
G. haemon Asteraceae endogall This wasp induces the plant to produce dark, grayish spherical structures within Asphondylia galls, each of which contains a wasp larva. Dorchin et al. (2015) found these galls within galls made by A. solidaginis, A. rosulata, and A. pseudorosa, mostly in leaf-snap galls. photo of Galeopsomyia haemon galls within a Asphondylia solidaginis leaf-snap gall
photo by Beatriz Moisset
(CC BY-SA 4.0)
Dorchin et al. (2015)
Rhopalomyia Gall midges that can induce a variety of galls on a variety of hosts, but those on goldenrods tend to induce the plant to form small insect chambers with soft walls. These chambers may be hidden by a large, spongy mass of plant tissue and/or clusters of leaves, or they may occur unobscured, protruding directly from stems and leaves. Dorchin et al. (2009)
R. fusiformae E. graminifolia,
E. caroliniana
inflorescence, mostly Very similar to the galls formed by R. pedicellata, but without a pedicel, often lacking even some of the bottom tapering section, appearing as though welded to the host tissue. This is a minor difference in gall shape, but it correlates with differences in insect morphology. Galls occur on stems, leaves, and inflorescences. context shot of many R. fusiformae galls
photo by Don Sutherland
CC BY-NC 4.0
Dorchin et al. (2009)
R. lobata E. graminifolia bud Multi-chambered galls on apical and lateral buds. They start as 1 cm globular swellings within shoot tips or clustered around the shoot tips. Several leaves surround the spongy mass at the gall base. Eventually the leaves loosen and the whitish tissue reveals many larval chambers. The leaves extend beyond the gall, thinning towards the apex. Photo of R. lobata galls on lateral buds of Euthamia
photo by Jason Michael Crockwell
Photo (2) of R. lobata galls on lateral buds of Euthamia
photo by Christian Grenier
CC0 1.0
Dorchin et al. (2009)
R. pedicellata E. graminifolia inflorescence, mostly Pod-like structures attached to stems, leaves, and/or inflorescences. Delicate, slender gall with a single chamber. Green to purplish-red with longitudinal ridges, tapered at both ends. Proximal end has a long, slender stalk ('pedicel') that attaches to the rest of the plant. Two generations per year, at least. Close up of R. pedicellata gall on Euthamia
photo by Sequoia Janirella Wrens
CC BY-NC 4.0
Context shot of R. pedicellata galls on Euthamia
photo by Sara Rall
CC BY-NC 4.0
Dorchin et al. (2009)
galls on Solidago:
Asphondylia Larvae of this gall midge genus develop in chambers composed of modified plant tissue with an inner fungal lining. For several species the walls of the chambers are made of leaf tissue that has the appearance of being glued together, forming either a rigid cone at the site of a bud or a "spot-welded" blister between two leaves. Others develop within modified flower-heads. There are often several generations per year. The organ and host species may vary through the year. Dorchin et al. (2015)
A. monacha S. juncea, S. erecta, S. uliginosa, S. altissima bud Early Spring Generation (only observed on S. altissima): Bud galls directly off of rhizomes at the soil line: Wider and harder than normal buds, single chamber lined with white mycelium. Or, slightly later in the season, bud galls at the tip of longer sprouts, stunting them and making them slightly thickened.
Summer Generation (on S. juncea, S. erecta, S. uliginosa, but not S. altissima): Much more conspicuous apical rosette bud galls, lined with mycelium, 15-30 rosette-units, forming a spherical gall complex at the shoot apex. Occasionally found on lateral buds of S. uliginosa, but rarely found there on other host species. S. uliginosa-derived adults were smaller in size as well. The authors speculated that these might represent a separate species (but also distinct from the S. uliginosa-galling Asphondylia below).
photo of spring generation A. monacha bud gall
early spring gall
photo by Daniel McClosky
(CC BY 4.0)
A. monacha bud gall cluster
summer bud gall
photo by Sequoia Janirella Wrens
(CC BY-NC 4.0)
Dorchin et al. (2015)
A. rosulata S. rugosa, S. gigantea,(S. uliginosa), (S. altissima), ((S. ulmifolia)) leaf snap,
Spring-Early Summer: Leaf Snap galls (either hosts): Multiple leaves appear joined together at a single blister (actually the leaves are "glued" together when the leaves are still developing) to make a single chamber lined with white mycelium. Unlike those produced by A. solidaginis, these galls are often located very near the plant apex, giving rise to a gradient in forms from leaf snap to bud galls. This gradient is visible in the example observation.
Mid-Late Summer: Bud galls (only on S. rugosa) and only on apical buds. A single, conical chamber in the middle of a rosette of leaves. The chamber is lined with white mycelium.
Photo of a gradient of A. rosulata galls, from leaf-snap galls to a bud gall, on Solidago rugosa
bud gall and leaf-snap galls on Solidago in subsect. Venosae in Tennessee.
photo by Ashley M Bradford
(CC BY-NC 4.0)
Photo of A. rosulata leaf-snap gall on Solidago rugosa
leaf-snap gall on S. rugosa in Pennsylvania
photo by Daniel McClosky
(CC BY 4.0)
Dorchin et al. (2015)
A. silva S. caesia bud Small, single-chambered bud galls at shoot tips. Several very short leaves press together to form a single, mycelium-lined chamber. photo of an A. silva gall on Solidago caesia
gall on S. caesia in Pennsylvania
photo by Daniel McClosky
(CC BY 4.0)
Dorchin et al. (2015)
A. solidaginis S. altissima, S. gigantea bud Spring-Summer: Leaf-snap galls (either host): Multiple leaves appear joined together at a blistering point (actually the leaves are "glued" together while the leaves are developing) to make a single chamber lined with white mycelium.
Summer: Bud galls (only on S. altissima) on apical and/or axillary buds (3-5 cm in diameter), with a single, conical chamber in the middle that is lined with white mycelium. Unlike in Rhopalomyia solidaginis galls, the central chamber is not obscured by the surrounding modified leaves; it is visible without dissection. The gall walls are lined with thick white mycelium. The surrounding rosette of bunched leaves is also smaller in size, and flatter (not tufted). R. solidaginis bud galls usually contain several chambers per gall; those of A. solidaginis contain a single chamber. Another cecidomyiid, Camptoneuromyia adhesa, sometimes emerges from snap-galls like these.
A. solidaginis leaf snap galls photo by Lena Struwe
leaf snap galls
photo by Lena Struwe
(CC BY-NC 4.0)
A. solidaginis bud gall photo by Timothy Frey
bud gall
photo by Timothy Frey
(CC BY-NC 4.0)
A. solidaginis leaf snap gall with pupal exuviae
leaf snap gall with protruding pupal exuviae
photo by Vitaly Charny
(CC BY-NC 4.0)
Dorchin et al. (2015)
Felt (1907)
A. sp.1 "S. bicolor-galler" S. bicolor rosette A. monacha-like galls (and insects) that are distinct from A. monacha according to a molecular phylogenetic analysis. Could be the same species as A. sp. "S. sempervirens galler". One insect from a S. uliginosa rosette gall also sorted into this clade, while others from that host species sorted into A. monacha photo of a dense, A. monacha-like gall on Solidago bicolor gall on S. bicolor
photo by Daniel McClosky
(CC BY 4.0)
See also Fig. 6 in Dorchin et al. (2015).
Dorchin et al. (2015)
A. sp.1 "S. sempervirens-galler" S. sempervirens, ((S. mexicana)) bud A. monacha-like galls (and insects) that are distinct from A. monacha according to a molecular phylogenetic analysis. Could be the same species as A. sp. "S. bicolor galler". One S. uliginosa rosette gall adult also sorted into this clade, while others sorted into A. monacha. Unlike A. monacha, this species also makes lateral bud galls.
See Charley Eiseman's (@ceiseman) blog post for a photo by Noah Charney of this gall, along with details of its discovery and insects reared from it.
See also Fig. 5 in Dorchin et al. (2015) for a photo of these terminal bud galls.
photo of an A. monacha-like gall on Solidago sempervirens gall on S. sempervirens
photo by Sara Rall
(CC BY 4.0)
Dorchin et al. (2015)
A. sp.1 "S. uliginosa-galler" S. uliginosa rosette See comments for A.  sp. "S. sempervirens galler" and A. sp. "S. bicolor galler". Distinct, at least, from A. monacha, though that species also forms rosette bud galls on S. uliginosa. Dorchin et al. (2015)
A. sp.2 S. nemoralis leaf snap Leaf snap galls similar to those made by Asphondylia species are observed rarely on this species, but the agent responsible is unknown. Dorchin et al. (2015)
A. sp.2 S. tortifolia° bud A. rosulata-like galls have been observed in October, but the agent responsible is unknown. Dorchin et al. (2015)
A. pumila S. patula bud Aggregated bud galls with mini-rosettes, like those made by A. monacha, have been observed on this species, but as of 2015 the insect remained unknown. These have since been attributed by Plakidas (2018) to a new species, Asphondylia pumila presumably on morphological grounds. The alternative hypothesis alluded to in Dorchin et al. (2015), that these galls are simply an expansion of the host-range of A. monacha (or another Asphondylia species), was not directly addressed.
My notes: These three observations of bud galls on S. patula were found in close vicinity to typical A. monacha galls on their typical host, S. juncea.
Photo of aggregated bud galls on S. patula
Aggregated bud galls atop S. patula
photo by Daniel McClosky
(CC BY 4.0)
Dorchin et al. (2015), Plakidas (2018)
A. sp.2 S. odora bud Bud galls like those made by A. monacha have been observed on this species, but the insect remains unknown. Could be A. monacha, or another insect. Dorchin et al. (2015) , this observation
A. sp.2 S. chapmanii bud Bud galls like those made by A. monacha have been observed on this species, but the insect remains unknown. Could be A. monacha, or another insect. Perhaps conspecific with the one on S. odora, a closely-related host. gallformers unknown inducer page
A. sp.2 S. rigida, S. ptarmicoides bud Bud galls like those made by A. monacha have been observed on this species, but the insect remains unknown. Could be A. monacha, or another insect. I'm grouping those occurring on hosts in Solidago subsect. Ptarmicoidei here. gallformers unknown inducer page
A. sp.2 S. ulmifolia bud Bud galls roughly like those made by A. rosulata have been observed on this species, but the insect remains unknown. They have a distinctive appearance with narrower rosette leaves. gallformers unknown inducer page
A. solidaginis S. pacifica bud East Asia.
Moved to Schizomyia solidaginis in Elsayed et al. (2018)
Gagné & Jaschhof (2017)
Elsayed et al. (2018)
Asteromyia Larvae of this gall midge genus usually develop in flat blisters between the faces of a single leaf. The galls are composed of discolored plant tissue with a brittle inner fungal lining. There are often several generations per year.
A. carbonifera Solidago leaf spot Black or black-and-white blisters on leaves, lined internally with white mycelium. Interesting evolutionary biology research has been done in this system, particularly in the lab of John Stireman at Wright State University. Different lineages of A. carbonifera induce differently-shaped galls. Some are black, some black-and-white, and some have raised white cushions. The fungus that lines the interior of these galls is Botryosphaeria dothidea. Photo by Asteromyia carbonifera gall on Solidago leaf
photo by Matt Parr
(CC BY-NC-SA 4.0)
Photo of Asteromyia carbonifera gall on Solidago leaf
photo by Sequoia Janirella Wrens
(CC BY-NC 4.0)
Photo of Asteromyia carbonifera galls on Solidago leaf
photo by Ryan (iNat user: brick1083)
(CC BY-NC 4.0)
Stireman et al. (2010)
A. modesta Solidago, Erigeron, Conyza°°, Grindelia, Symphyotrichum leaf spot Leaf blisters. The larvae reside in cryptic pockets of leaf tissue that may be purple but are often the same green color as the surrounding leaf tissue.
The species is probably polyphyletic as currently circumscribed, with two distinct clades. One clade is itself polyphyletic if A. tumifica is separated from A. modesta. Both clades include some individuals sampled from galls on Solidago. Charley Eiseman accidentally reared this midge from a leaf with more prominent leaf-mines, and photographed both the blister and the midge.
Photo of Asteromyia modesta gall on Doellingeria leaf
on Doellingeria umbellata
photo by Charley Eiseman
(CC BY-NC 4.0)
Stireman et al. (2010)
Bug Tracks blog post
A  tumifica Solidago stem Spongy outgrowth that partially or wholly encircles a stem. Sometimes very low on stem.
Nested within one of two A. modesta clades, rendering that clade paraphyletic. Perhaps this insect taxon will be folded into a revised concept of A. modesta in the future, or perhaps that taxon will be split up.
Photo posted to bugguide here by John van der Linden, identified by Raymond Gagné
Photo of an A. tumifica gall
photo by Tom Murray
(CC BY-NC 4.0)
Stireman et al. (2010)
Dasineura Species in this large genus of gall midges have diverse life histories and gall forms. The species known from North American goldenrods make deformed and swollen terminal shoot buds with clustered and blistered leaves. The orange larvae develop between the leaves, but exit the gall and pupate in the soil. The shoot sometimes recovers and grows beyond the gall, leaving a deformed section of stem with very short internodes.
D. folliculi S. rugosa, S. gigantea, ((S. altissima)), ((S. canadensis)), ((S. caesia)) bud Shoot tip bud galls that resemble other bud galls, but are looser and show evidence of feeding (yellowish spots, sometimes deforming the leaves somewhat) on the more-distal portions of the gall leaves. The galls may be hairy or smooth depending on the host species. The larvae exit the galls to pupate in the soil. Dasineura larvae are orange. Similar, but smaller and white-colored larvae present in galls may be Macrolabis americana, an inquiline. Photo of a D. folliculi bud gall
on S. rugosa in Pennsylvania
photo by Daniel McClosky
(CC BY 4.0)
Photo of a D. folliculi bud gall
on S. gigantea
photo by David (iNat user: davidenrique)
(CC BY-NC-SA 4.0)
Dorchin et al. (2006),
Dorchin et al. (2007),
Dorchin et al. (2009b)
D. virgaeaureae S. virgaurea variable? Eurasia. There are several descriptions of the galls caused by this midge. Galls in shoot tips, capitula, leaf rolls, and swollen flower buds have all been ascribed to this fly. Dorchin et al. (2006)
Epiblema Larvae of this moth genus (at least those making goldenrod galls) bore into stems, where they initiate narrow swellings in which they overwinter. These structures might not be strictly considered galls by some; they lie somewhere on the continuum of gall formation to herbivory-responsive growth. Miller (1976) referred to them as "rudimentary galls".
E. scudderiana S. altissima, S. canadensis, S. gigantea, S. juncea, S. ulmifolia, S. nemoralis,((Heterotheca subaxillaris)), ((Symphyotrichum ericoides)) stem Narrowly ellipsoid stem-swelling galls. Sometimes irregularly shaped, often with vertical scars. Univoltine; the larvae enter the stems as late instars and overwinter in the gall. Before winter, the caterpillar spins a silk funnel that guides the emerging adult moth to the exit hole, which is plugged with a wagon wheel-shaped bung. Branches often proliferate at or above the gall. photo of Epiblema scudderiana gall on Solidago stem
on Solidago stem
Photo by Reiner Jakubowski
(CC BY-NC 4.0)
Miller (1963),
Miller (1976),
Brown et al. (1983)
Eurosta Most (all except E. latifrons?) of these Tephritid fruit flies develop in bulbous galls on stems of Solidago species, usually at least partially underground (rhizomes). However, the most commonly observed species develops on above-ground stems.
E. comma (S. juncea, S. missouriensis, S. rugosa) rhizome Swellings on rhizomes very near soil line. Sometimes peanut-like in outline. Steyskal & Foote (1977) give a reasonable rationale for earlier authors' confusion of the hosts of E. elsa and E. comma; they assign E. elsa to S. juncea and E. comma to S. rugosa. Current databases (e.g. ITIS) synonymize E. elsa with E. cribata. photo of Eurosta comma gall on Solidago juncea rhizome
photo by Daniel McClosky
(CC BY 4.0)
bugguide, Cedar Creek (2000), Novak & Foote (1980)
E. cribata S. juncea, S. sempervirens rhizome "Crown Gall" that begins near the soil line (or just under), but grows upwards and is mostly above-ground at maturity. Like those of E. comma, the galls resemble peanuts somewhat. Ming (1989) included E. conspurcata and E. reticulata in synonymy with this species. photos and illustrations in Novak & Foote (1980) (paywalled) bugguide, Arthr. Fl., Sutton & Steck (2005)
E. fenestra ? rhizome According to Sutton & Steck (2005) this is also a member of the E. comma species complex. They mention that it has likely never been found in Florida, despite earlier reports, which were misidentifications of E. floridensis or other members of the E. comma species complex. photos and illustrations in Novak & Foote (1980) (paywalled) Sutton & Steck (2005)
E. floridensis S. fistulosa rhizome Galls are similar to those made by E. comma and E. fenestra. Arth. Fl., Sutton & Steck (2005)
E. lateralis S. chapmanii stem Similar to the common "ball galls" made by E. solidaginis, but the gall radius is much smaller (Foster, 1934, as "E. nicholsoni", later realized to be synonymous with E. lateralis by Foote (1964)). Another synonym: E. donysa. Only known from Brevard Co., Florida, at least recently. It may be critically endangered (Sutton & Steck (2005)), or even extinct. They give S. odora as the host, but the host is presumably S. chapmanii based on location, which was not regularly segregated from S. odora then. They point out a very old record by Wiedemann (1830) also possibly of this species in the "Indien" (sic) River area of Florida. Foster (1934) points to galls found "near Titusville", "near Malabar", and "from 5.5 miles southwest of Indian River" all near the coast. Arth. Fl., Sutton & Steck (2005)
[E. latifrons] Solidago sp. ? Sutton et al. (2002) speculate that this fly probably develops from undiscovered galls on Solidago. Sutton et al. (2002)
E. solidaginis S. altissima, S. gigantea, (S. canadensis), (S. rugosa) stem Nearly spherical galls, made on the aboveground stem, rather than on the rhizome like most of the rest of the goldenrod-galling members of this genus. The exterior vestiture of the gall depends on the identity of the host species. They are hairy when on S. altissima (presumably also when on S. canadensis and S. rugosa), but smooth and shiny when on S. gigantea. There is a great wealth of literature on the evolution of this system. Gall diameter is a function of the genes of the insect, not the host plant. Insects that produce galls with larger diameters are more likely to survive attack by parasitic wasps, whose ovipositors are unable to penetrate the thicker galls. However, larger galls are more attractive to birds, which eat the larvae in winter. There is also interesting research on host-species specialization by different populations of this fly (on S. altissima vs. on S. gigantea), and the divergent selective pressures at play. The galls are so frequent on S. altissima in the mid-Atlantic that the presence of galls has been suggested as an identification aide for distinguishing S. altissima from S. canadensis, although some sources suggest that S. canadensis can also (rarely?) host this fly. photo of E. solidaginis stem gall on Solidago altissima
on S. altissima
photo by Daniel McClosky
(CC BY 4.0)
photo of E. solidaginis stem gall on Solidago gigantea
on S. gigantea
photo by iNat user: auroradj29
(CC BY-NC 4.0)
Bucknell University Solidago Gall Website, Moffatt et al. (2019), Stoltzfus (1989)
Eutreta Tephritid fruit flies whose larvae bore through stems, usually inducing galls. They have a variety of hosts in Asteraceae and Verbenaceae.
Eutreta hespera Solidago sp. rhizome Reared once from rhizomes of "a goldenrod" near Custer, South Dakota. The adult flies have been collected along streams and grassy slopes from the Dakotas westward, throughout much of western North America. Stoltzfus (1974)
Eutreta novaeboracensis *S. rugosa, (S. spp.) rhizome, stem Larvae bore through both rhizomes and above-ground stems, inducing galls as swellings of those organs. The stem-borers emerge earlier than the rhizome-borers (and are bivoltine rather than univoltine), so these two groups might represent cryptic sister species. Stem-galls can be found near the ground, sometimes described as crown galls. "Eutreta sparsa" is sometimes attributed to these and other galls on North American Astereae, but this is actually a South American species that does not make galls on Solidago rhizomes, instead associating with Stachytarpheta (Verbenaceae) branches. drawing of Eutreta novaeboracensis galls on the rhizomes of Solidago altissima
drawing by Millett T. Thompson (1907)
(public domain)
bugguide, Stoltzfus (1974), Thompson (1907)
Galeopsomyia in Eulophidae, a family of chalcidoid wasps
G. haemon Asteraceae endogall This wasp induces the plant to produce dark, grayish spherical structures within Asphondylia galls, each of which contains a wasp larva. Dorchin et al. (2015) found these galls most frequently within leaf snap galls, but also found them in bud galls made by A. solidaginis, A. rosulata, and A. pseudorosa. photo of Galeopsomyia haemon galls within a Asphondylia solidaginis leaf-snap gall
photo by Beatriz Moisset
(CC BY-SA 4.0)
photo of Galeopsomyia haemon galls within an Asphondylia solidaginis bud gall
photo by iNat user @jennimartin
(CC BY-NC 4.0)
Dorchin et al. (2015)
Gnorimoschema Larvae of some members of this large moth genus develop within stem swellings on goldenrods. Several species have been described from goldenrods, but not all are universally accepted as distinct. The larvae bore into the shoot apex and then travel down the center of the stem. Deformed, stubbier leaves at the shoot apex give a clue to the presence of the larva before it begins to make its gall. The larvae then backtrack upwards, where they induce a stem swelling with a large internal cavity. There is one larva per gall. Before spinning a cocoon they bore an adult exit hole. This hole is variably capped with plant- and/or insect-derived substances. Miller (2000) gave evidence that these "bung hole" structures were diagnostic of particular species, arguing that differences in their construction were not merely consequences of different host goldenrod building material, but were intrinsic to the species of insect. Whether all the species in his monograph on the group are distinct enough to warrant their own names (particularly in the case of G. jocelynae) remains debated, but with some support from molecular phylogenies (Nason et al. 2002). Miller gave species names with neuter suffixes, but I don't know which form is correct according to nomenclatural rules so I will follow the suffixes present in online checklists and more recent literature instead.
G. gallaeasteriella S. flexicaulis, Symphyotrichum saggitifolium, (Solidago caesia, S. uliginosa, Eurybia divaricata, and perhaps many others) stem No bung is formed; the adult exit hole is difficult to see because it is capped with plant epidermal tissue instead. It is located in the top third of the gall, like most other goldenrod Gnorimoschema galls, but unlike those of the otherwise very similar G. gallaespeciosum, which are instead formed near the gall equator.
This species might be conspecific with G. gallaediplopappum, a moth with unknown gall biology (Miller 2000).
Unlike other Gnorimoschema species, the leaves at the shoot apex may not be deformed by the presence of the larva, but the shoot itself may have its growth arrested.
Are all these different host reports really referring to the same species of moth? They are all basically woodland Astereae, but I can't help but wonder whether there have been some mistakes in host identification. Miller (2000) reported that he could only find these galls on Symphyotrichum saggitifolium. From these he reared adults that matched Kellicot's (the original species authority). Judd (1962) could not find any galls on S. caesia despite there being large numbers of these plants adjacent to and within a S. flexicaulis site with many galls. Busck (1911) considered the problem of host identification, and concluded that the species may simply have a wide host range. His "S. latifolia" is our S. flexicaulis; his Aster corymbosus apparently refers to E. divaricata. I still can't help but wonder whether all these hosts might really be misidentified plants in the Symphyotrichium cordifolium species complex (which includes S. saggitifolium), which are variable and difficult to identify in the absence of flowers.
woodcut of gall by D. S. Kellicott (1878)
woodcut of gall by D. S. Kellicott (1878)
Gnorimoschema gall on Solidago caesia
Gnorimoschema gall on S. caesia
photo by Rob Curtis
(CC BY-NC-SA 4.0)
Nazari & Landry (2012), Miller (2000), Judd (1962), Kellicott (1878), Busck (1911)
G. gallaesolidaginis S. altissima, S. canadensis, (S. gigantea) stem Probably the most common Gnorimoschema moth that forms galls on goldenrods. These are ellipsoid stem galls with an exit hole stuffed with characteristically light-colored "bung". The bung tissue is essentially flush with the surrounding plant tissue, which forms a slightly raised ring around the hole. The galls are wider than those made by Epiblema moths. Miller (1963) mentioned that there are other species in this genus that make galls on other Solidago species. His later monograph on them (2000) listed eight species, most of which have been reported from Solidago species. Later, Heard & Kitts (2012) compared G. gallaesolidaginis on S. altissima and S. gigantea. Nason et al. (2002) considered this to either contain a single differentiating species (into semispecies) onto the two respective host-groups (S. altissima/canadensis and S. gigantea), or two barely-isolated cryptic species, in which case G. jocelynae is the species name for the group that feeds on S. gigantea. photo of Gnorimoschema gallaesolidaginis spindle gall on dead Solidago stem
photo by Daniel McClosky
(CC BY 4.0)
photo of Gnorimoschema gallaesolidaginis spindle gall on living Solidago stem
photo by Sarah Scharf
(CC BY-NC 4.0)
Miller (1963), Heard & Kitts (2012), Nazari & Landry (2012)
G. gallaespeciosum (S. speciosa, S. jejunifolia, S. rigidiuscula, S. pallida) stem Elliptical stem galls similar to those of G. gallaesolidaginis, but differing in exit hole placement nearer the equator and the lack of bung tissue (instead being capped with plant epidermis). Reported from S. speciosa, but the type specimen is from Ramsey Co., MN, which is out-of-range for S. speciosa in the new, strict sense. The host is more likely S. rigidiuscula, a goldenrod species segregated from S. speciosa in the broad sense. S. pallida and S. jejunifolia were also segregated from *S. speciosa, so they, too, are provisionally included here as a potential hosts. Miller (2000)
G. gibsoniella S. rigida, Symphyotrichum pilosum stem S. rigida was reported as the host plant for the type collection, but Miller (2000) reared these from galls on Symphyotrichum pilosum stems. The initial description by Busck here notes that it forms galls just above the ground, and Miller also noted this, mentioning that he only found them after mowing tall grass. Nazari & Landry (2012), Busck (1915)
G. jocelynae S. gigantea stem Very similar to galls by G. gallaesolidaginis, but with dark bungs that are recessed into the exit hole. The bung material is not flush with the surrounding plant epidermis. This is the name Miller (2000) gave to the host-race derived from G. gallaesolidaginis, when that species established a cryptic sister species on S. gigantea (Nason et al. 2002). The main visible difference is in the bung coloration. Miller performed larva transplant experiments to confirm that bung colors were a function of the larvae's parental host species, not their current host species. However, Nason et al. (2002) point out that these exit hole characteristics could be idiosyncratic to particular plants; Miller only examined three specimens for each reciprocal experiment. I wonder whether the larva transplant experiments might have a different interpretation than Miller's: The bung material could reflect the host species that the larva spent most of its life feeding on, which in his experiments would be the plant with the donor-gall, not the plant with the receiver-gall. Works after Nason et al. (2002) refer to these moths as "G. gallaesolidaginis, gigantea host-race". photo of Gnorimoschema spindle gall on Solidago gigantea stem
Gnorimoschema gall on S. gigantea
photo by iNat user rangerrich
(CC BY-NC 4.0)
Nazari & Landry (2012)
G. salinaris S. sempervirens, S. missouriensis, S. juncea, (S. gigantea, S. ulmifolia) stem Differences from G. gallaesolidaginis galls: (1) bung material is dark brown to black in color, (2) galls tend to be lower on the stem, (3) the interior surface of the bung (not visible from outside) is cushioned by layers of spongy silk material, (4) different host species. The original description, by Busck, noted that the insects were reared from galls similar to those of G. gallaesolidaginis, but occurring on S. sempervirens. Miller (2000) associated this species with additional hosts inland: the S. juncea species complex. He referred to these plants as "S. juncea/missouriensis", but based on the locations of his collections, he was almost certainly only collecting galls from S. juncea. Nazari & Landry (2012) list S. gigantea as a host according to one Michigan record, but this might be G. gallaesolidaginis/G. jocelynae. Miller (2000) attributed some galls on S. ulmifolia to this species, but noted that these were rare and only found at one site with abundant galls on S. juncea. Miller may have been following a taxonomic treatment of the three main host species that does not match the current circumscriptions of these species. Some of his statements, particularly that S. sempervirens and S. juncea hybridize, sound a little strange, and he seems to imply that these three species are closely related. Both molecular- and morphology-informed phylogenies imply otherwise. I wonder whether some of Miller's hosts might have been S. uliginosa or other species. However, all reported hosts do have smooth stems in common.
Miller (2000) noted that some of the adult characteristics that Busck said differentiated this species from G. gallaesolidaginis were not as consistent as Busck claimed. He instead focused more on the gall characters (host plant ID and bung characters), and presented evidence that this species makes galls closer to the ground, and with a more variable shape in outline, ranging from elliptical to pear-shaped. The gall shape begins perfectly vertically-symmetric in the ultimately pear-shaped galls, becoming asymmetric only with age. The bung itself is dark in color, like that of G. jocelynae, and surrounded by a ring of tissue that may be slightly raised. The bung tissue is flush with this ring, like in G. gallaesolidaginis and unlike in G. jocelynae.
photo of Gnorimoschema spindle gall on Solidago juncea stem
Gnorimoschema gall on S. juncea
photo by Daniel McClosky
(CC BY 4.0)
Nazari & Landry (2012), Miller (2000), Busck (1911)
Janetiella I can't find much on these. Gagné & Jaschhof (2017) call the genus a "diverse assemblage".
J. inquilina Solidago sp. ? aka Oligotrophus inquilinus Felt 1908; on "S. canadensis", which, at the time, could have referred to several species in Solidago subsection Triplinerviae. I presume that these are inquilines, from the name. Gagné & Jaschhof (2017)
Lasioptera Members of this gall midge genus have a variety of life histories, but most form stem galls. Gagné & Jaschhof (2017)
L. solidaginis Solidago stem Irregular, elongated stem-swelling galls. "Knotty" in appearance according to Felt (but so many of the galls are mismatched in that work). See this observation by M.J. Hatfield on bugguide, verified by Gagné and also here bugguide, Gagné & Jaschhof (2017)
Lestodiplosis Larvae of this gall midge genus are usually predators of other cecidomyiid larvae, but some have been reported to be gall formers, maybe in error. Gagné & Jaschhof (2017) give the following species from Solidago galls, but are not claiming that they are the gall-makers. Gagné & Jaschhof (2017)
L. carolinae S. canadensis (presumably sensu lato) bud Reported by Felt to be the initiator of the gall, but given the life history of others in the genus, more likely a predatory species. Found in a rosette bud gall on "S. canadensis". Maybe this is a synonym of Rhopalomyia carolina(e), itself a synonym of R. solidaginis? Found in Asheville, NC Gagné & Jaschhof (2017)
L. rugosae Solidago sp. New York Gagné & Jaschhof (2017)
L. triangularis Solidago sp. leaf New York Gagné & Jaschhof (2017)
P. anthracina (S. californica) bud Bud galls cluster on stems near where they emerge from rhizomes. Usually buried in humus, but not truly subterranean. Univoltine, unlike P. atra. Reported from "S. velutina" in California - these plants are now in the segregate species, S. californica, according to John Semple's website. Goeden & Teerink (1997)
P. atra S. altissima, S. gigantea, S. canadensis, S. erecta, S. nemoralis, S. odora, S. rugosa, S. speciosa, Symphyotrichum drummondii bud Spring Generation: Large stem galls at the base of the host plant, each containing several larvae.

Summer Generation: Lateral bud galls that look like Brussels sprouts initially, and eventually open as the fly matures. The terminal bud is also sometimes galled, but usually in addition to lateral galls. (My observation: When the terminal bud is galled, it is often much larger than the accompanying lateral galls.) The gall chamber is large and not sealed, much larger than the fly larva or pupa, and is slightly open at the distal end. The chamber has the appearance of being inset into the stem somewhat, although the surrounding tissue may not technically be derived from the stem, but rather from other plant tissues. At maturity, the rosette of leaves surrounding the gall typically flatten and grow away from the gall, giving the gall a more rosette-like appearance.

(My note: At this stage, these galls, particularly the terminal ones, can superficially resemble those of Rhopalomyia solidaginis and Asphondylia solidaginis. However, those midge-induced galls have distinct chambers formed by one or few young leaves. The midge gall chambers are cryptic, translucent conical structures set atop the host stem rather than appearing hollowed-out within stem-like tissue.) Each gall has only one larva, unlike in the spring generation.

This species probably has many other hosts, including some outside Solidago, although some researchers have speculated that there may be cryptic host-races within P. atra, some of which may have fully speciated (Philips & Smith 1998).
photo of spring Procecidochares atra gall

photo of spring Procecidochares atra gall, cut open
Spring Generation gall
photos by Daniel McClosky
(CC BY 4.0)
photo of Procecidochares atra galls
Summer Generation galls
photo by Jason Dombroskie
(CC BY-NC 4.0)
another photo of Procecidochares atra galls
photo by Yann Kemper
vertical section  of Procecidochares atra gall
summer generation, vertical section through terminal bud gall
photo by Daniel McClosky
(CC BY 4.0)
Wikipedia, iNat obs, bugguide, Philips & Smith (1998), Eiseman (2024) for host records
P. minuta (Solidago), Astereae stem Recorded from a stem gall on Solidago californica in Wasbauer (1972): "C. D. A. 1 In stem gall; CALIFORNIA: Palomar Mt., San Diego Co., IX-19-1964, E. D. Algert". This species is known to produce galls on a number of composite host species, including rabbitbrushes. I'm not sure this record is from a correctly identified host plant; rabbitbrushes can look vaguely like goldenrods before blooming. Wasbauer (1972)
P. polita (S. virgata, S. chrysopsis), (((S. sempervirens))),(((S. mexicana))) ? Reared from Solidago sp. "small, roundish galls" by Girault (1913) in Virginia. Reported from galls of Solidago sp. by Johnson (1910). However, Aldrich (1929) wrote that accounts of this species being reared from Solidago galls are in error, and actually refer to P. atra due to some nomenclatural confusion at the time in the literature.
Much later, Ibrahim (1980) attributed "Solidago stricta" stem galls collected in Dade County, Florida to P. polita. At that time, "Solidago stricta" would have referred to what is now known as S. virgata or possibly S. chrysopsis at that location (see John Semple's website for details). There are older records for collections in the Jacksonville area (Sutton & Steck 2005) and the Falls Church, Virginia area (Aldrich 1929). Sutton & Steck (2005) caution that many details in Ibrahim (1980) are inaccurate and repeat known mistakes from earlier literature, though they don't mention the P. polita record specifically.
The adult flies are apparently easily distinguished from P. atra by having entirely yellow legs rather than having black femora and coxae. Goeden & Norrbom (2001) say it's distributed along the east coast, from Massachusetts to Florida. None of these post-1929 sources describe the gall.
This fly seems to be restricted to the east coast of the USA, so its host plant, if it is a Solidago species, is probably a coastal species. Wasbauer (1972) includes some records from "S. stricta" galls as well.
Aldrich (1929), Ibrahim (1980), Goeden & Norrbom (2001), Sutton & Steck (2005)
Rhopalomyia Gall midges that can induce a variety of galls on a variety of hosts, but those on goldenrods tend to induce the plant to form small insect chambers with soft walls. These chambers may be hidden by a large, spongy mass of plant tissue and/or clusters of leaves, or they may occur unobscured, protruding directly from stems and leaves. Dorchin et al. (2009)
R. anthophila S. altissima capitulum Capitulum (flower-head) galls among the flowers of the host. Cylindrical, or like a truncated cone. Fuzzy and whitish. Inner chamber conical, resembling the shape of other Rhopalomyia insect chambers, with thin walls. Photo of an isolated R. anthophila gall on the inflorescence of Solidago altissima
photo by Kevin Keegan
macro image of a R. anthophila gall
photo by Dan Mullen
(CC BY-NC-ND 2.0)
cluster of R. anthophila galls, some with persisting pupal exuviae
a highly-galled flowering stem; several galls have persisting pupal exuviae
photo by Karen Yukich
(CC BY-NC 4.0)
Dorchin et al. (2009)
R. bulbula S. juncea rhizome bud Only a spring generation is known, but the insect is presumably multivoltine;
Spring Generation: "Clustered on rhizomes, at the bases of spring shoots. The gall resembles a bud, with acute apex and base. Surface is smooth and white, with green stripes where exposed to light." Single chambered.
photograph of R. bulbula gall from Felt (1917)
photo by E. P. Felt (1917)
Dorchin et al. (2009), Felt (1917)
R. capitata S. gigantea, S. leavenworthii, (S. rugosa), ((S. canadensis)) bud Spring Generation: Few (1-8) conical chambers surrounded by disorganized small leaves, sheathed (initially at least, sometimes loosening) by several wide leaves. Distinctly more conspicuous than R. solidaginis spring galls.
Summer Generation: Apical bud gall with many small leaves of uniform length in the middle, surrounding many (6-20) closed larval chambers. Wide leaves also sheath these galls. The uniformly-small leaves give the overall gall complex a flat-topped appearance. Whereas tufts of leaves that comprise the summer generation gall complex formed by R. solidaginis form discernible mini-rosettes, each surrounding a larval chamber, in R. capitata the gall leaves are not obviously so-organized, perhaps as a consequence of there being many more chambers.

Stireman et al. (2005) demonstrated that Rhopalomyia leaf-bunching gall midges sorted into two well-separated clades, one from specimens raised from S. altissima galls and the second from specimens reared from S. gigantea and S. leavenworthii galls. Dorchin et al. (2009) resurrected the name R. capitata for the latter clade, and described some morphological differences from R. solidaginis sensu stricto.

Note: The separation between the two may not be this clean. In the upper Great Lakes region there are leafy galls on S. gigantea that more closely resemble those made by R. solidaginis. Eiseman (2024) recently reared flies identified to this species (ID by morphology by Raymond Gagné) from single-chambered R. solidaginis-like galls on S. rugosa - a new host for R. capitata. Some of these galls terminated short axial shoots.
photo of R. capitata spring generation bud gall
spring generation
photo by Daniel McClosky
(CC BY 4.0)
photo of typical summer generation R. capitata bud gall
summer generation
photo by iNat user mamiles
(CC BY-NC-ND 4.0)
Stireman et al. (2005), Dorchin et al. (2009), Eiseman (2024)
R. clarkei S. rugosa, S. altissima leaf outgrowth Small, conical, single-chambered. Usually on lower leaf surface, but can also appear on upper surface or on stems. When on leaves, attached at a major vein. Green to yellow-green and covered with hairs. Very young galls with a tuft of hair at base. Multivoltine. Less frequent on S. altissima.
(My observation: There are several gall observations on iNaturalist that fit this description, and are currently identified as R. clarkei, but they do not all closely resemble one another. They may represent different stages of development, different presentations on different host species, or misidentifications with some other gall-maker.)
Photo of a R. clarkei leaf gall
photo by Adam Kranz
(CC0 1.0)
Photo of a R. clarkei leaf gall
photo by Sara Scharf
(CC BY-NC 4.0)
macro photo of a brown R. clarkei leaf gall
photo by Ann McKenzie
(CC BY-NC 4.0)
Dorchin et al. (2009)
R. cruziana ((S. californica)) capitulum? From an unknown gall from an unidentified Solidago species growing in the Santa Cruz mountains in California. The host species to the left is my speculation based on the ranges of Solidago species native to this region. Dorchin et al. (2009) infers that the gall is probably a capitulum gall because the adult insects closely resemble other capitulum-gallers in this genus. Dorchin et al. (2009)
R. gina S. juncea leaf outgrowth Like R. clarkei galls, but usually on upper side of leaf and with a corresponding scar or little tail on the opposite side. Hairless, probably reflecting the vestiture of the host plant. See Figs. 68-69 in Dorchin et al. (2009) for images.
My note: Fig. 69 shows a leaf with what might be pubescence on the abaxial surface (in addition to the normal cilia at the leaf margin), which makes me wonder whether the host plant is correctly ID'd as S. juncea.
Dorchin et al. (2009)
R. guttata S. bicolor capitulum Forms teardrop shaped galls that retain the capitulum-pedicel. Difficult to find among regular flower-heads. Dorchin et al. (2009)
R. hirtipes S. juncea bud Forms fleshy bud galls at the shoot apex, often arresting shoot growth while the plant is still very short. Gall initially has a tapered tip, but this disappears with growth. The whole gall eventually becomes ovoid and reminiscent of a potato. Spongy and usually multi-chambered. See also R. thompsoni for a similar gall that appears earlier in the season and mostly underground. Photo of an opened R. hirtipes bud gall
photo by Marie-Ève Garon-Labrecque
(CC BY-NC 4.0)
Photo of a R. hirtipes bud gall
photo by Catherine Klatt
(CC BY-SA 4.0)
R. hirtipes bud gall photo showing the plant flowering from lateral buds under the gall
not always arresting growth
photo by Charles and Kathy Appell
(CC BY-NC 4.0)
Dorchin et al. (2009)
R. inquisitor S. gigantea leaf outgrowth? Originally described as an inquiline in R. capitata galls, but this could not be replicated by Dorchin et al. (2009). The did notice R. clarkei-like galls (except smooth-surfaced) on S. gigantea, though, particularly on leaves from within Dasineura folliculi galls, and conjectured that these R. clarkei-like galls might be the real galls occupied by this species. Perhaps Felt (original description) confused D. folliculi galls with R. capitata galls, and then concluded that R. inquisitor was an "inquiline" that way? However, Dorchin et al. (2009) were unable to rear any adults from these R. clarkei-like galls on S. gigantea, so the galls where R. inquisitor resides remain unclear. An example of these galls is probably shown here: by Sara Rall. Close up of Rhopalomyia galls on Solidago gigantea leaves
photo by Daniel McClosky
(CC BY 4.0)
Photo of R. inquisitor galls, maybe, on S. gigantea leaves
click to zoom to see small leaf-outgrowths. Leaf clustering may be caused by D. folliculi. Host plant is S. gigantea.
photo by Sara Rall
(CC BY-NC 4.0)
See also Figs. 66-67 in Dorchin et al. (2009) for reference images.
Dorchin et al. (2009)
R. racemicola (S. altissima, S. fistulosa) capitulum Green, bristly, onion-shaped capitulum galls, sometimes found in aggregations. A collection of galls on S. fistulosa was tentatively attributed to this species by Raymond Gagné . Gagné (1971) described the history of confusion around the causal agent of these galls, and assigned to Schizomyia the galls containing bright orange larvae (which chew a hole through the gall as larvae to pupate elsewhere; originally described as Cecidomyia racemicola by Osten Sacken). Felt (1907) reared adults from similar galls on "S. canadensis" (probably S. altissima) racemes in North Carolina. These adult flies do belong in Rhopalomyia, according to Gagné (1971) and Dorchin et al. (2009); Gagné (1971) considered their larva and gall therefore unknown.

Dorchin et al. (2009) tentatively ascribe the bristly, aggregated onion-shaped galls on the stems of S. fistulosa as well as whatever the true galls Felt (1907) originally reared the species from (his description in 1915 is of S. racemicola galls) to R. racemicola.
Felt (1907), Gagné (1971), Dorchin et al. (2009)
R. solidaginis *S. altissima, S. canadensis, S. rugosa bud Spring Generation: Inconspicuous, shoot tip rosette bud-galls, often stunting the shoot. Unlike the later generation, these typically enclose a single, white, conical gall-chamber, but sometimes several gall-chambers are connected longitudinally.
Summer generation: Each of multiple (2-5) chambers is surrounded by a group of very short and narrow leaves, which are in turn surrounded by longer and wider leaves to form a distinct rosette-subunit within the gall complex. The whole complex itself forms a conspicuous mass of leaves. This is a very common gall in the mid-Atlantic states. See R. capitata for more.
photo of Rhopalomyia solidaginis bud gall on Solidago shoot apex
summer generation
photo by Brad Walker
(CC BY-NC 4.0)
photo of dug-up spring generation bud gall on Solidago altissima
spring generation
photo by Daniel McClosky
(CC BY 4.0)
vertical section through R. solidaginis summer generation bud gall on Solidago altissima
summer generation, vertical section
photo by Daniel McClosky
(CC BY-NC 4.0)
See also Figs. 70, 72 in Dorchin et al. (2009) for images of spring generation galls.
Stireman et al. (2005); Dorchin et al. (2009)
R. thompsoni S. altissima, (S. juncea), (S. rugosa) rhizome bud Spring Generation: Solitary or clustered, bulbous, fleshy masses with 1-8 chambers each. Start on rhizomes (underground) but become apparent above ground by emergence time in early May.
Second Generation: Brownish, globular multi-chambered swellings of the rhizomes that stay underground until late September when they become apparent above the soil surface for adult emergence. Both galls and adults resemble R. hirtipes. Dorchin et al. (2009) could only find galls that reared adults similar to the type of R. thompsoni from galls from S. atissima, but Felt had listed the other two species as hosts.
Dorchin et al. (2009)
R. sp. (S. fistulosa-stem-galler) S. fistulosa stem Aggregated stem galls, each gall a hairy grayish oval, with a single chamber each. The aggregate commonly has a star-like structure. They appear most similar to R. racemicola galls. Might be responsible for the gall in this observation. Dorchin et al. (2009)
Schizomyia Gagné & Jaschhof (2017)
S. racemicola Solidago spp. capitulum Greenish-purplish onion-shaped capitulum galls alongside normal capitula in the inflorescence. Gall exterior is smooth. Gall-maker larva is bright red-orange. It exits the gall as a larva and pupates elsewhere. photo of S. racemicola gall on S. ulmifolia
on S. ulmifolia
photo by Daniel McClosky
(CC BY 4.0)
photo of S. racemicola gall on S. altissima
on S. altissima
photo by Daniel McClosky
(CC BY 4.0)
S. solidaginis S pacifica See Asteralobia solidaginis entry. bugguide
T. pura S. gigantea
S. altissima
stem "[in May and June]...puparia were taken from often indistinct apical stem swellings in Solidago gigantea... and, possibly S. canadensis [my note: probably S. altissima this far south]... from which the adults emerged in the laboratory in June-July of the same year." - later mentions another record of S. altissima serving as a host in the midwest Sutton et al. (2002)
T. webbi Solidago sp. capitulum "M. F. Canova states that the specimen was taken from a gall in the flowerhead of goldenrod." Sycan Glen, OR. The adult insects closely resemble T. michiganiensis and T. pura, neither of which have known host species (at least by 1951). Quisenberry (1951)

There are some records of Trupanea spp. infesting goldenrod flower-heads, but do they form galls?

Wasbauer (1973) gives a secondary record for galls of Aciurina bigeloviae on Solidago, but this species probably doesn't regularly gall Solidago (?)

Foote & Blanc (1963) ascribe a collection of galls on Solidago in Inyo Co., CA to A. ferruginea, but this fly typically galls rabbit-brushes. Maybe a mistaken host ID?

See also Aster Yellows phytoplasma, which can induce phyllody in Solidago.

°observed in Maryland (??)
°°I think this Conyza species is probably C. canadensis, which is back in Erigeron now.

1These entries are for insects that induce galls resembling those of Asphondylia monacha, but were found on other host Solidago species, and were divergent phylogenetically.
2These entries are for the un-studied (to my knowledge) insects that induce Asphondylia-like galls on other host Solidago species. These are known only from the appearance of galls on these goldenrods; the midges themselves have been neither reared nor described. These may be the work of known Asphondylia midges, A. monacha and A. solidaginis in particular, on occasional/accidental host species. They may also represent unrelated gall-making organisms.

Unexpected / Interesting goldenrod gall observations

Asphondylia-like bud galls on southeastern USA Solidago sp.

Leaf deformation (and maybe a snap-gall?) on Solidago sp. in MS:

A bud gall on Solidago way out-of-range in Washington State:

Rhopalomyia solidaginis-like bud gall in appearance, but on S. gigantea in MN/WI:

P. atra on unidentified southern goldenrod species:


Aldrich (1929):

Arth. Fl. = Arthropods of Florida website by Florida State Museum of Entomology:

Bucknell University Eurosta biology page:

Cedar Creek Ecosystem Science Reserve (2000):

Dorchin et al. (2006):
Dorchin, N., Scott, E. R., Abrahamson, W. G. (2006) First Record of Macrolabis (Diptera: Cecidomyiidae) in America: A new inquiline species from Dasineura folliculi galls on goldenrods. Systematics 99(4): 656-661.

Dorchin et al. (2007):
Netta Dorchin, Carolyn E. Clarkin, Eric R. Scott, Michael P. Luongo, Warren G. Abrahamson, Taxonomy, Life History, and Population Sex Ratios of North American Dasineura (Diptera: Cecidomyiidae) on Goldenrods (Asteraceae), Annals of the Entomological Society of America, Volume 100, Issue 4, 1 July 2007, Pages 539–548, https://doi.org/10.1603/0013-8746(2007)100[539:TLHAPS]2.0.CO;2

Dorchin et al. (2009):

Dorchin et al. (2009b):
Dorchin, N., Scott, E. R., Clarkin, C. E., Luongo, M. P., Jordan, S. and Abrahamson, W. G. (2009) Behavioural, ecological and genetic evidence confirm the occurrence of host‐associated differentiation in goldenrod gall‐midges. Journal of Evolutionary Biology, 22: 729-739. doi:10.1111/j.1420-9101.2009.01696.x

Dorchin et al. (2015):
Dorchin, N., Joy, J. B., Hilke, L. K., Wise, M. J., Abrahamson, W. G. (2015) Taxonomy and phylogeny of the Asphondylia species (Diptera: Cecidomyiidae) of North American goldenrods: challenging morphology, complex host associations, and cryptic speciation. Zoological Journal of the Linnean Society, 174: 265-304. doi:10.1111/zoj.12234

Eiseman (2024):
Eiseman, C. S. (2024) Procecidochares atra Loew (Tephritidae) and Rhopalomyia capitata Felt (Cecidomyiidae) (Diptera) reared from single-chambered rosette galls on rough-stemmed goldenrod (Asteraceae: Solidago rugosa Mill.). Proceedings of the Entomological Society of Washington 125 (2): 273-277. https://doi.org/10.4289/0013-8797.125.2.273

Elsayed et al. (2018):
Elsayed, A. K., Yukawa, J., Tokuda, M. (2018) A taxonomic revision and molecular phylogeny of the eastern Palearctic species of the genera Schizomyia Kieffer and Asteralobia Kovalev (Diptera, Cecidomyiidae, Asphondyliini), with descriptions of five new species of Schizomyia from Japan. Zookeys 808: 123-160.

Heard & Kitts (2012):

Ibrahim (1980):

Felt, E. P. (1915):

Felt, E. P. (1917):
Felt, E.P. Key to American Insect Galls. New York State Museum Bulletin 200.

Foote (1964):
Foote, R. H. (1964) A new synonym in the genus Eurosta (Diptera: Tephritidae). Proceedings of the Entomological Society of Washington 66 (1): 61.

Foote, R. H., Blanc, F. L., and Norrbom, A. L. (1993) Handbook of the Fruit Flies (Diptera: Tephritidae) of America North of Mexico

Goeden & Teerink (1997):

Goeden & Norrbom (2001) Life history and description of adults and immature stages of Procecidochares blanci, n. sp. (Diptera: Tephritidae) on Isocoma acradenia (E. Greene) E. Greene (Asteraceae) in Southern California. Proceedings of the Entomological Society of Washington 103 (3-4): 517-540.

Kellicott, D. S. (1878) A new gall moth and notes on larvae of other gall moths. The Canadian Entomologist 10(11): 202-204.

Miller (1963):

Miller (1976):

Ming (1989): Thesis, referenced in Foote et al. (1993)

Moffat et al. (2019):

Philips and Smith (1998):

Phillips (1923): https://www.jstor.org/stable/pdf/25003994.pdf

Plakidas, J. D. (2018):

Steyskal & Foote (1977):
Steyskal, G. C. and Foote, R. H. (1977) Revisionary notes on North American Tephritidae (Diptera), with keys and descriptions of new species. Proceedings of the Entomological Society of Washington 79 (1): 146-155.

Stireman et al. (2005):
Stireman, J. O., Nason, J. D., Heard, S. B. (2005) Host-associated genetic differentiation in phytophagous insects: General phenomenon or isolated exceptions? Evidence from a goldenrod-insect community. Evolution 59 (12): 2573-2587. https://doi.org/10.1554/05-222.1

Stireman et al. (2010):

Stoltzfus (1974):

Stoltzfus (1989):

Sutton et al. (2002)
Suton, B. D., Steck, G. J., DeFoe, D. (2002) New recoods of Tephritidae (Diptera) from Great Smoky Mountains National Park - II. Insecta Mundi 16 (1-3), pp. 1-8.

Sutton & Steck (2005):

Thompson (1907):
Thompson, M. T. (1907) Three galls made by cyclorrhaphous flies. Psyche 14: 71-74.

Quisenberry (1951):
Quisenberry, B. F. (1951) A Study of the Genus Tephritis Latreille in the Nearctic Region North of Mexico (Diptera: Tephritidae). Journal of the Kansas Entomological Society, Vol. 24, No. 2 (Apr., 1951), pp. 56-72

Posted on October 08, 2019 06:53 AM by ddennism ddennism | 34 comments | Leave a comment

September 11, 2018

Two Texas Toadshades

Trillium gracile, and T. ludovicianum may both be present in eastern Texas. These are my notes for distinguishing them from one another, taken from the monograph where John Freeman first described T. gracile and clarified the previously-hazy description of T. ludovicianum. Where metrics are given, I have omitted the extreme values, providing only the "typical" ranges (not in parentheses). Other Trillium also occur in Texas. By "leaves" I mean, technically, "bracts".

T. gracile T. ludovicianum
scape length : leaf length 3.2 - 3.5 2.4 - 2.8
shape elliptic
(elliptic-ovate to elliptic-oblong)
lanceolate or
broadly ovate
length 18 - 26 mm 24 - 40 mm
apex shape acuminate-blunt or obtuse acute or acute-rounded
length 21 - 35 mm 35 - 55 mm
anther sac
introrse latrorse
pollen color creamy - yellow olive - orange
anther connective
short-beaked short-rounded
carpel-height : stamen-length barely exceeding 0.5 ≥ 0.75
ovary x-section 3-angled 6-angled
stigma length 2.0 - 4.5 mm 4.5 - 10 mm
stigma attachment divergent
extending ovary outline into lyre-shape
initially continuous in outline with ovary
bending distal to point of attachment
outline smooth often prominently 6-ridged

I have seen comments suggesting that clump-formation and overall plant size differ between the two species, with T. ludovicianum being both more likely to form clumps and generally taller. These are not mentioned in Freeman's monograph. He gives an overlapping range of scape lengths for the two species, with T. gracile being actually taller on average (though it has petals that are about 2 cm shorter):

Trillium gracile: (16-) 20-32.5 (-36) cm long scapes
Trillium ludovicianum: (10-) 15-28 (-37) cm long scapes

Singlehurst et al. (2003) summarized the occurrences of Trillium in Texas. Changes from Freeman's monograph germane to their separation by morphology:

  1. T. gracile is listed as having elliptic to broadly ovate leaves.
  2. T. ludovicianum is listed as having clump-forming tendencies lacking in T. gracile

The two species are probably at least partially temporally isolated with T. gracile blooming later: late Mar -May vs. late Feb - early Apr.

Posted on September 11, 2018 07:03 PM by ddennism ddennism | 0 comments | Leave a comment

August 10, 2018


U. grandiflora U. perfoliata U. sessilifolia U. puberula U. floridana
leaf attachment perfoliate perfoliate sessile sessile sessile
tepal planar curvature whole tepal twirls along long axis, apex may flare tepal margins may roll outwards, apex may flare apex may flare apex may flare tepal twirls distally along long axis, apex may flare
tepal abaxial surface smooth raised orange-yellow bumps smooth smooth smooth
stem cross-section at nodes terete terete angled angled, with rough puberulence along ridges angled
leaf abaxial surface pubescent glabrous-glaucous glabrous-glaucous puberulent(-glabrous) glabrous

U. floridana also has a leaf-like bract (very, very near the flower) that is absent in its close relatives (U. sessilifolia, U. puberula)

Posted on August 10, 2018 07:25 PM by ddennism ddennism | 1 comment | Leave a comment

June 26, 2018

Two Erigeron in PA

Erigeron annuus and Erigeron strigosus are the two Erigeron species in PA with tapering leaf bases (rather than clasping leaves).

Flora of PA treatment uses vague descriptors to distinguish them (what constitutes "numerous leaves"?) that might be useful once the user is already familiar with the two.

Flora of North America entry (Guy Nesom, 2004) quickly distinguishes them from other Erigeron based on lack of pappus on ray florets, but not disc florets . This is pictured in my observation.
It then emphasizes stem vestiture, which might not be visible in many observations on iNaturalist. Even this emphasis includes quite a bit of overlap, apparently to accommodate some varieties of E. strigosus and to accommodate the fact that E. annuus sometimes has strigose hairs too.

Michigan Flora gets around this problem by ignoring the problematic E. strigosus var. septentrionalis (associating it with some forms of E. annuus), which makes for a cleaner couplet, but who knows? it might be an oversimplification:

"E. annuus: Middle region of stem glabrate to pubescent with all or many of the hairs long (0.5–1.2 mm) and spreading; principal cauline leaves usually elliptic to ovate, ca. 10–35 (–40) mm wide, with a few large teeth.

E. strigosus: Middle region of stem moderately to densely pubescent with only short (0.5 mm or less) mostly appressed-antrorse hairs; principal cauline leaves linear to oblanceolate, ca. 2.5–10 (–15) mm wide, entire."


Posted on June 26, 2018 12:34 AM by ddennism ddennism | 2 observations | 0 comments | Leave a comment

March 28, 2018

Two Blue Cohosh Species

Caulophyllum thalictroides and Caulophyllum giganteum are separate species according, as far as I can tell, mostly to this paper. However, it occurs to me, reading this paper, that physiological effects of early emergence could confound the determination of the morphological details used in this study.

For example, if the emergence and flowering phenology of C. giganteum is earlier, and if the vegetative characters that supposedly distinguish the species continue to expand and grow, as do many forest herbs, then the vegetative characters could appear larger for supposed C. giganteum plants just as a consequence of their head-start. This could be a problem as long as all the plants in this part of the study were sampled on the same day-of-the-year, rather than day-since-emergence (they were).

"On the collection date of the mass sample, 11 May 1982, C. giganteum had completed flowering while C. thalictroides was in anthesis." But how were such plants assigned species-identifications, then? Hopefully not by the same morphological characters that were used in the PCA!

The vegetative morphological characters in the single-population experiment:

Vegetative differences in C. giganteum (all longer and/or bigger):

  1. leaflet length and width of the first two leaves
  2. leaflet sinus length of the first two leaves
  3. primary petiolule length of the first two leaves
  4. terminal inflorescence length
  5. and a decrease in the degree of compounding of the second leaf.

The authors also show that flower size differences distinguish the species. (This part is from herbarium specimens across the ranges of all three species in the genus.)

  1. stamen length
  2. sepal length
  3. pistil length
  4. petal length
  5. ratio of filament length to anther length
    (but you shouldn't use ratios in this type of analysis)

In this case, they found convincing evidence of a bimodal distribution along PCA1 (composed of the above 5 characters, in decreasing order of importance, and with the same positive valence), which suggests two morphologically distinct species, one big-flowered and one small-flowered. However, this shows no evidence of the claimed phenological separation, and doesn't really show evidence of other traits that supposedly differentiate the species (flower number per inflorescence, perianth color). Herbarium specimens are not always the most representative examples of a given population, and there may well have been plants in the C. giganteum populations that had smaller flowers that were less conspicuous to the collectors.

A common greenhouse experiment might be necessary to determine whether there really is separation here, and I'd like to see evidence that organ expansion has completed by the time of its determination in the first part of this study. But maybe first I should observe some of these populations for myself:

The closest Caulophyllum locations to me:

For my late April trip to Shenandoah:

on the way down:

in and around Shenandoah:

Posted on March 28, 2018 07:43 PM by ddennism ddennism | 5 comments | Leave a comment

March 16, 2018

Three Similar Toadshades in SE USA

Trillium decipiens, T. reliquum , and T. underwoodii form a group of three closely related species. Here are my notes for distinguishing them from one another, taken from the monograph where the other two were first segregated from a broader concept of T. underwoodii.

T. decipiens T. underwoodii T. reliquum
stalk (scape)
erect erect decumbent*
stalk : leaf
length ratio
2.5 - 3.0
leaf tips don't touch ground
1.0 - 2.5
leaf tips often touch ground
1.6 - 2.0
leaf surfaces at or near ground level
carriage at flowering
divergent-spreading horizontal,
or curving back down to touch leaves
length : width ratio 3.0 - 3.5 3.5 - 4.0 3.5 - 4.0
broadly oblanceolate - obovate narrowly oblanceolate to narrowly elliptic usually narrowly elliptic,
but variable
length : width ratio 2 - 3 3.5 - 5 3.5 - 4
occasionally broader
color highly variable, from
green to yellow-purple to brown-purple
(rarely yellowish)
(rarely yellowish)
anther sac dehiscence lateral lateral introrse
stamen : carpel
height ratio
≈ 1.5 ≈ 1.5 ≥ 2
leaf shape lanceolate
(straight line from widest point to apex)
(straight line from widest point to apex)
broadly elliptic
(convex curve from widest point to apex)

*not nearly as decumbent as Trillium decumbens. In the T. reliquum population I visited, the stalk (scape) will sometimes only hint at 'laxness' with a slight 'S' bend, but at least some plants in a given population should have scapes that grow initially along the ground.

Posted on March 16, 2018 11:25 PM by ddennism ddennism | 2 observations | 0 comments | Leave a comment

February 21, 2018

Distinguishing Yellow Trout Lilies in E USA

It's easy to distinguish our three yellow trout lilies from one another when they are in-fruit, or dug-up. But what about when they're in-bloom? You know, when you notice them?

The presence of stolons can be inferred from the number of one-leaved, 'sterile' plants in a population. The stolon-producing species often produce carpets of plants in this stage; E. umbilicatum subsp. umbilicatum will only produce the occasional cluster of steriles, which are either same-aged siblings (clustered by a single fruit dispersal event) or offsets with the blooming-sized parent eaten/missing.

Clifford Parks and James Hardin (1963) carried out an exhaustive study of their floral characteristics and correlated them to stolon production, ploidy, and capsule shape. I thought the results of their paper might be useful to iNaturalists. They are summarized here:

E. rostratum E. americanum E. umbilicatum
subsp. umbilicatum
E. umbilicatum
subsp. monostolum
tepal carriage agape strongly reflexed strongly reflexed strongly reflexed
flower angle erect nodding nodding nodding
stolons 1+ 1+ 0 1
capsule shape
in profile
strongly beaked
rounded, truncate,
or apiculate
rarely merely truncate
capsule presentation held erect not erect
but still held off the ground
reclining on the ground reclining on the ground
or rarely just above
petal bases clearly auricled
encircling filaments
minutely auricled
or toothed
not auricled not auricled,
but margin irregular
green coloration
on abaxial side of tepals
none none or slight none present
pale spot
at base of inside of tepals
absent absent in 90%
otherwise vague or small
always present,
but sometimes small
always present
often prominent and large
dark flecking
on perianth
absent absent or slight absent or slight,
but variable
always present,
few to many
style thickness
just below point of
stigmatic divergence
thickened thickened remains thin remains thin
stigma lobes swollen
anther & pollen color yellow
or brown-lavender
rarely yellow
rarely yellow
ploidy diploid tetraploid diploid diploid

Not included: E. americanum subsp. harperi, because the authors questioned its distinctiveness. It's mainly distinguished from E. americanum subsp. americanum by having (1) more strongly-apiculate capsules and (2) stigma lobes that are 'distinctly grooved distally' and variously described as 'recurved' or merely 'divergent'. It is documented from Alabama, Georgia, Mississippi, and southern Tennessee. Geraldine Allen and Kenneth Robertson consider it to be more reliably distinct and single it out in their treatment of the genus for The Flora of North America entry.

Posted on February 21, 2018 09:28 PM by ddennism ddennism | 5 comments | Leave a comment

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