', {"anonymize_ip":true});

December 03, 2021

White-flowered stonecrops of eastern North America

If you trust iNat's ID suggestions, then there's only one white-flowered stonecrop in the eastern US, Sedum ternatum. However, as anyone familiar with the pitfalls of computer suggestions might guess already, there are actually more than that. One in particular, Sedum glaucophyllum, is frequently misidentified as S. ternatum but tantalizingly close to having enough observations to be included in the next computer vision model. This post is intended to raise awareness of its existence and provide a comparison and guidance how to tell the two species apart.

I first encountered S. glaucophyllum on iNat while reviewing observations for S. ternatum and noticing different leaf arrangements than the plants I was familiar with. Almost at the same time, I was made aware of the existence of S. nevii through a plant give-away at the NC Native Plant Society. This made me look into these additional species a little bit more. Both have white flowers very similar to S. ternatum and neither of them are "known" by the current computer vision model.

Sedum Comparison
Botanical drawings of S. ternatum and S. nevii from Britton, N.L., and A. Brown, 1913, An illustrated flora of the northern United States, Canada and the British Possessions. Note the leaves in whorls of three on S. ternatum sterile shoots and opposite or whorled on flowering shoots as compared to leaves in spirals on sterile shoots of S. nevii with alternate leaf arrangement on the flowering shoots. S. glaucophyllum was split from S. nevii later and therefore did not have a separate drawing in this publication. However, it is similar in appearance but more variable and typically a little larger than S. nevii.

Both S. glaucophyllum and S. nevii are much rarer finds than the common woodland stonecrop and more specialized in their habitat. A glance at their distribution maps shows that both overlap with S. ternatum but are more restricted in their range and do no overlap with each other. S. glaucophyllum is endemic to Virginia and West Virginia with a few isolated occurrences in North Carolina and Maryland, while S. nevii is mostly found in Alabama with some populations in Tennessee and Georgia. S. glaucophyllum is found in cracks on cliffs and rocky habitats with moderately high pH soil and is absent in acidic rock outcrops. S. nevii grows in shallow, gravelly soils on steep bluffs of gneiss, an acidic, granite-like rock.

Sedum distribution map
Distribution of Sedum ternatum, S. glaucophyllum, and S. nevii in the Eastern US based on BONAP data to color in the distribution for each plant.

Since the current ranges of S. nevii and S. glaucophyllum do not overlap, location should be a clue for identifying these if found growing wild. (However, both species may be used as garden plants beyond their native range.) Digging a little deeper, it appears S. glaucophyllum differs from the other two species by chromosome count. While S. nevii always has 6 chromosome pairs and S. ternatum has 8, S. glaucophyllum shows 14 chromosomes or more, suggesting that it may have originated as an allopolyploid of the other two species.

It should be mentioned that there is one more species of white-flowered Sedum present in the eastern US, S. pusillum. However, this species is more similar to the elf orpine, Diamorpha smallii, currently included in the CV model and therefore more likely to be confused with that species than with S. ternatum. It is restricted to granite outcrops from Anson County, NC, to southwestern Georgia.

Posted on December 03, 2021 05:41 by annkatrinrose annkatrinrose | 0 comments | Leave a comment

Milestones and meta-data

I noticed I haven't posted anything in my journal for a while, so I guess it's time for a bit of a recap! (Also, it's final exam week so naturally I'm looking for something to distract me from grading...) It's been a little over two years since I joined the iNaturalist community. The pandemic put the brakes on some of the activities I had planned when I started, such as a plant phenology project with our local chapter of the North Carolina Native Plant Society and a BioBlitz at the AppState Nature Preserve in spring 2020. In addition to stay-at-home orders and lock-downs preventing access to some of my usual hiking spots, converting all our classes to remote teaching took its toll on spare time!

However, I still managed to break a few personal milestones. At some point over this past year, I reached 1,000 species observed. I meant to keep an eye on that number to see when it happened, but managed to miss that moment. One day I checked and I was already well over the mark, currently at 1,170. This is a moving target, of course, as IDs may change based on community input. I did manage to catch the exact time I broke the 5,000 observations threshold. Obs #5,000 is a life list first for me! When I started out, I imported a lot of stuff from my Flickr account. That certainly helped to get my observation numbers up quickly as many of these are actually from before I joined iNat. I still have a backlog of about a decade worth of photos to go through that I didn't post to Flickr so I'll be able to add additional pictures and some more past observations once I get the time for that. Somewhere along the way I managed to sneak into the spot of top observer for the Blue Ridge Parkway, although I guess that position depends on how competitive eraskin is going to get over it.

I'm grateful for the many people who have provided IDs for my observations! I've learned so much from this and discovered new species I didn't know existed because they were omitted from the field guides I have. When I started, I decided that I would try to pay back to the community by making at least as many IDs for others as I post observations. That turned out to be a lot of fun and I'm currently at about a 3:1 ratio of IDs vs. observations. I love digging through the unknowns for my area to see what I can recognize, and I also frequently go through Plantae for things I can narrow down to at least family if not genus or species. Just recently, I've discovered the need for IDs in Denmark and that looks like a lot of fun, too! Since I grew up in northern Germany, a lot of the plants are 'old friends' and have me on a trip down memory lane, being a child again picking wildflowers in the woods with grandma. This was well before I developed an interest in botany, but thankfully iNat knows most of the German common names for a lot of these as often that is the only name I know for them.

The forum is another great resource with oodles of tips and tricks. I used some of these to create the figures below to get an overview of all my observations and identifications on iNat so far. The link for the observation and identification heat maps was provided by bouteloua in a feature request, and the link to obtain your identifier stats can be found in the IdentiFriday thread. Note that the colors in the pie charts have no relation to the colors on the heat maps - I just happened to accidentally pick a very similar color scheme and didn't feel like doing them all over again. I guess the bottom line from this is that I really like to focus on the plants (~3/4 of my own observations, and >90% of my IDs for others).

iNat Observations

iNat IDs

Last but not least, a call-to-action! If you know something about plants and would like to help nudge some of those stuck at Plantae due to ID conflicts, here's a handy ID URL provided by arboretum_amy in yet another forum thread.

Posted on December 03, 2021 02:31 by annkatrinrose annkatrinrose | 1 observation | 0 comments | Leave a comment

September 12, 2020

The Nipplewort-Imposter

This plant has been bugging me since we first noticed it last year and all the folks with plant ID apps on their phones helpfully identified it as Nipplewort (Lapsana communis) introduced from Europe. I checked it out on the computer at home, and the USDA database had a report of it only in one of the more southern counties in NC but not where we were hiking. I subsequently tried to find it in my field guides and came up empty-handed. Even Weakley's Flora just mentions it as being uncommon in NC but doesn't deem it important enough to provide a description.

That's odd, I thought, especially since it seemed to be growing everywhere along trails and roadsides in the woods. Maybe the plant we saw was actually something else? Like a rookie, I had missed to get a picture of the leaves though, so I had to wait a year for it to pop up again before I could investigate further. So here we are, one year later, and I think I finally have figured it out: It appears to be the native Allegheny Hawkweed (Hieracium paniculatum), and all the plant ID apps out there don't know anything about it. Instead, they frequently misidentify it as nipplewort.

Further digging into herbarium records confirms that the hawkweed should be a lot more common around here than the introduced nipplewort. Both species occur in the mountains of western North Carolina with the nipplewort's range overlapping with that of the hawkweed. But where Hieracium paniculatum is reported as "common in the mountains" in "dry to mesic forests and woodlands, especially where disturbed, such as logging roads, trailsides, wooded borders," Lapsana communis is listed as "very rare." It was collected in 1938 in Haywood County, 1995 in Madison County, 2002 in Swain County, 2005 in Ashe County, and 2010 in Buncombe County. That's it for NC herbarium collections.


Range comparison of nipplewort (purple) and Allegheny hawkweed (pink and purple). The map was colored in using data from Vascular Plants of North Carolina. The plant drawings are from the illustrated flora by Britton & Brown, published in 1913 (now public domain), and were downloaded from the USDA PLANTS database.

The best way to tell the plants apart seems to be by the leaves. Nipplewort's leaves are variable along the plant but the lower leaves have a large terminal leaflet and one to four small side leaflets and regularly toothed margins. Allegheny Hawkweed produces leaves only on the stem with basal leaves usually lacking, and they are thin and elongated by comparison and have an irregularly toothed to entire margin.

It seems the iNat computer vision algorithm is not the only one that gets this one wrong. (On all the plants I checked, it never actually offered what I think is the correct ID.) Other apps, like Picture This, misidentify the plant as well. It seems to be a self-perpetuating ID error - people identify the plant as nipplewort because that is what the app suggests, which then teaches the app to identify this as nipplewort again on similar photos. I suspect a lot of the "nippleworts" out there on iNat are actually Hieracium paniculatum, at least here in the Southern Appalachians. Please feel free to comment on this or help fix some of the incorrect IDs!

Posted on September 12, 2020 22:09 by annkatrinrose annkatrinrose | 4 observations | 5 comments | Leave a comment

November 24, 2019

Chickweeds in North Carolina

The purpose of this page is to provide an identification aid for chickweeds in North Carolina, predominantly the type found blooming in the woods in the mountains in spring. There are two genera commonly referred to as chickweeds: Stellaria and Cerastium. Here in NC, we have three native members of Stellaria (S. pubera, S. corei, and S. alsine) and two native members of Cerastium (C. nutans and C. brachypodum), with non-native and invasive species from both genera also present. This sounds like a mess to sort out, but if the goal is to identify native Stellaria it is actually fairly easy to tell these apart from the others. By far the most common one found in the woods in the mountains is the star chickweed, S. pubera.

The first step would be to distinguish native from non-native species, and Stellaria from Cerastium. If the plants are in bloom, the size of the flowers and shape of the petals is the best indicator, with different leaf shapes to support identification. As shown on the figure below, S. pubera has flowers twice the size of the others (1/2 inch across, compared to 1/4 inch) and is also known by the common name giant chickweed because of this. The characteristic that sets Stellaria apart from Cerastium is the depth of the notches on the petals. All these plants have five petals, but in Stellaria they are notched so deeply that they often appear as ten, whereas the notches don't go as far in Cerastium.


Comparison of flower size and characteristics of common native chickweed (left) and three common invasive chickweeds (right), colored in with Photoshop to make it easier to distinguish sepals and petals. The original flower pictures are from the illustrated flora by Britton & Brown, published in 1913 (now public domain), and were downloaded from the USDA PLANTS database.

A large-flowered plant found growing in the woods is most likely S. pubera. However, S. corei also occurs throughout the mountains and has similarly large flowers. The way to tell between S. pubera and S. corei when in bloom is by the length of the sepals. In S. pubera they are shorter than the petals, while in S. corei they are longer and extend past the petals when the flower is fully open. The pictures below illustrate this characteristic. Note these are young flowers that have just opened up, so the anthers are bright red. As the flowers mature, they might lose the bright color. The anthers on S. pubera stay dark, often an orange-brown, while I've seen some flowers of S. corei where the anthers were lost or not as strikingly colored.


Comparison of the two chickweeds native to NC mountain forests: The one on the left is the common star chickweed (Stellaria pubera) and was a rescue from a construction site; the one on the right is the rare Tennessee chickweed (Stellaria corei) purchased from a native plant nursery.

As mentioned above, the ranges of these two chickweeds overlap, with S. pubera common throughout the mountains and Piedmont, while S. corei is rare and restricted to the mountains and maybe upper Piedmont. Both species prefer rich forest habitats, while the third native Stellaria species, bog chickweed (S. alsine), is a wetland specialist and only occurs in the southwestern part of the state.


The maps were colored in using data from Vascular Plants of North Carolina for the native species and BONAP for the non-native ones. The plant drawings are from the USDA website and not copyrighted (original source: Britton & Brown: An illustrated flora of the northern United States, published 1913). They are scaled to each other for size comparison.

There are several non-native species in this genus and only the two most common ones are shown in the figure above. (The others are less common and more scattered.) Common chickweed, S. media, appears to occur throughout the state, with gaps in the occurrence data probably due to underreporting rather than an actual absence in those counties. Grass-leaved chickweed, S. gramineum, is also wide-spread. Besides differences in the flower size and their propensity to grow in human-disturbed areas, the shape of the leaves is another way to tell the invasives from the natives. S. media has more heart-shaped leaves, and S. graminea has more grass-like leaves compared to the natives.

No discussion of chickweed would be complete without at least mentioning the second genus, Cerastium, commonly referred to by the name chickweed. As explained above, these can be distinguished from Stellaria by the less deeply notched petals. The most common native species to encounter from this genus is nodding chickweed, C. nutans, which is fairly common in rich woods in the mountains and rare in the Piedmont. The second native species, S. brachypodum, has only few reports in the state so far and may have actually been introduced.


The maps were colored in using data from Vascular Plants of North Carolina for the native species and BONAP for the non-native ones. The plant drawings are from the USDA website and not copyrighted (original source: Britton & Brown: An illustrated flora of the northern United States, published 1913). They are scaled to each other for size comparison.

There are at least five non-native Cerastium species in the state and only the two most common ones are shown in the figures above. These are invasives of disturbed areas and distributed throughout the state. Gaps in the occurrence data are probably due to underreporting rather than an actual absence in those counties. Other non-native species are less common and more scattered throughout the state. All of these would mostly occur in human-disturbed areas, such as roadsides or as garden weeds. Sticky chickweed (C. glomeratum) is an annual weed covered in sticky hairs and with sepals extending beyond the petals, whereas mouse-ear chickweed (C. fontanum) is a mat-forming perennial with stolons that root where they rest on the ground and has sepals shorter than its petals.

Posted on November 24, 2019 18:58 by annkatrinrose annkatrinrose | 2 comments | Leave a comment

November 13, 2019

Trout Lilies in North Carolina

The purpose of this page is to provide an identification aid for trout lilies (genus Erythronium) in North Carolina. This is a fun one! Misidentifications run rampant in this genus - guilty of it myself - due to a fairly recent split into two species that doesn't seem to have trickled down yet into popular field guides. It takes a closer look at certain plant features according to more recent botanical manuals to sort them out.

The two species in question are E. americanum (the "original" trout lily) and E. umbilicatum (dimpled trout lily), which was split out and described as a separate species in 1963. Both have yellow flowers and mottled leaves. It turns out that E. umbilicatum actually is the more common one in the state, but this fact is nearly impossible to discern from field guides targeting the lay person. Out of a dozen pictorial wildflower guides for NC or the surrounding area on my book shelf, more than half only list E. americanum and make no mention of E. umbilicatum. Three provide prominent treatment and a picture for E. americanum and do acknowledge that another species exists, but seemingly as an afterthought. Only one book gives E. umbilicatum the more in-depth discussion but happens to get the identification features mixed up, erroneously stating that this species has auricles on the tepals, which actually is a distinguishing characteristic of E. americanum. None of the books have pictures of both species showing distinguishing features. In conclusion, popular field guides are of no help in this matter and will lead to misidentifications of E. umbilicatum as E. americanum.

Even herbarium data has to be taken with a grain of salt as many old specimens identified as E. americanum may in fact represent records of E. umbilicatum. The curators of the range maps caution about this and tried to account for it by considering only recent records and those that have been reexamined and confirmed, but there may still be some errors and an underrepresentation of actual occurrences in the maps. Both BONAP and SERNEC data suggest that E. umbilicatum is the more wide-spread species in NC. E. umbilicatum is common in the mountains and southwestern Piedmont, while E. americanum occurs less frequently in the Piedmont and is rare in the mountains.


(Map data from BONAP, top, and Vascular Plants of North Carolina, bottom.)

The first clue to species identity in this case may be habitat type. E. americanum is described as a species of basic mesic forests and rich bottomlands, limited to very rich, high pH soils. This rules out most habitats in the mountains and Piedmont, which tend to have low pH acidic soils. E. umbilicatum is not as picky about soil pH and grows in a wide range of forest types, including those acidic soils typical for the Southern Appalachians.

The best way to identify to species level based on morphology when in bloom is to look for auricles ("ears") on the innermost tepals. Other characteristics like the color of the pollen or tepals are apparently not reliable diagnostic features due to their high variability. Only E. americanum has these auricles while E. umbilicatum does not. The picture below shows what to look for (highlighted by the circles in the enlarged picture).

(Image source: Wikimedia, public domain; see Flickr for another great picture showing the auricles)

However, the best stage to distinguish the two species is when they are fruiting. E. umbilicatum is named for its umbilicate capsule, meaning it has a dimple in the top resembling a belly button. The capsules of E. americanum have rounded or pointed tips instead. (For a side-by-side comparison, check out the capsule pictures on Carolina Nature). The stalk that is holding the capsule is weak and flops over, causing it to rest on the ground in E. umbilicatum, while it is able to stand upright and hold the capsule "arching gracefully like a swan" as I've seen it described in one account for E. americanum.

(Image source: Wikimedia, shared by user Doppelbrau with a CC BY-SA 4.0 license)

E. umbilicatum is further divided into subspecies based on the presence or absence of stolons.

Posted on November 13, 2019 14:02 by annkatrinrose annkatrinrose | 6 comments | Leave a comment

November 10, 2019

Clethras in North Carolina

There are two species of Clethra (summersweet or sweet pepperbush) native to North Carolina that are often confused and this page is supposed to provide some guidance on identification. Their ranges actually do not overlap, so for plants found growing wild, it is safe to assume that any Clethra found growing in the mountains (or more rarely in the foothills) is C. acuminata, whereas any Clethra found in the coastal plain (or more rarely in the Piedmont) is C. alnifolia. (For plants in cultivation, this neat separation of course doesn't hold true. Most plants found in public plantings and gardens are cultivars of C. alnifolia.)

Growth habit, leaves, and bark can be diagnostic when trying to distinguish between the two species based on morphology. C. acuminata is a large shrub to small tree 10-12 ft big on average, whereas C. alnifolia is a thicket-forming shrub usually no taller than 6 ft. Older stems of C. acuminata have reddish and peeling bark ('cinnamon bark' giving it one of its common names, cinnamon clethra), wheres the stems of C. alnifolia are brown-gray with thin and smooth bark. The leaf shapes are what give these plants their scientific names. C. acuminata has pointed leaves with concave sides along the tip (acuminate) and finely toothed margins, whereas C. alnifolia leaves resemble alder (Alnus) leaves and are blunt or pointed with straight sides and serrated margins that do not extent all the way to the base. If the plants are in bloom, it is possible to use flower scent as an indicator as well. C. alnifolia has a sweet fragrance that is hard to miss (hence its common name summersweet), while C. acuminata has a more spicy fragrance that is barely noticeable.

The NC range map above was colored in using data from the Vascular Plants of North Carolina website. The plant drawings are from the USDA PLANTS database and not copyrighted (original source: Britton & Brown: An illustrated flora of the northern United States, published 1913). They are scaled to each other - C. acuminata has indeed larger leaves compared to C. alnifolia. For another comparison of the leaves of the different Clethras and similar species, also see the Native Plants of the Carolinas and Georgia website. (C. tomentosa listed on that page is now mostly treated as a variety or synonym of C. alnifolia and not a separate species.)

Posted on November 10, 2019 17:25 by annkatrinrose annkatrinrose | 0 comments | Leave a comment

Hepaticas in North Carolina

The purpose of this page is to provide an identification aid for liverleaf (genus Hepatica) in the mountains of North Carolina. There are two species/varieties (depending on source) native to North Carolina, Sharp-lobed Liverleaf (Hepatica acutiloba, syn. Hepatica nobilis var. acuta) and Round-lobed Liverleaf (Hepatica americana, syn. Hepatica nobilis var. obtusa), and their ranges overlap in the mountains and western Piedmont.

H. acutiloba is common in rich cove and northern hardwood forests in the mountains and rare in the higher elevations of the western Piedmont, whereas H. americana is common in moist to rich forests in the Piedmont and rare in the lower elevations of the mountains. Based on their reported ranges shown in green in the USDA PLANTS database maps below, it is probably safe to assume that any Hepatica observed in the State Parks around the High Country of northwest North Carolina is H. acutiloba.

When trying to distinguish between the two species based on morphology, it is diagnostic to get a good view of their leaves. H. acutiloba has rhombic leaves with parallel sides tapering to an acute tip, whereas H. americana has strongly rounded leaves with convex sides. In the absence of leaves, some features of the flowers may aid in identification as well. The flowers are subtended by three bracts, which in H. acutiloba have acute tips and often show between the sepals when the flower is viewed from above, whereas they are rounded and seldom show in H. americana. H. acutiloba is more likely to have white flowers with more than 6 sepals, while these occur more rarely in H. americana.


The NC range map above was colored in using data from the Vascular Plants of North Carolina website. The plant drawings are from the USDA PLANTS database and not copyrighted (original source: Britton & Brown: An illustrated flora of the northern United States, published 1913). For more pictures comparing these two species, also see the Native Plants of the Carolinas and Georgia website.

Posted on November 10, 2019 01:23 by annkatrinrose annkatrinrose | 1 comment | Leave a comment

Spring Beauties in North Carolina

The purpose of this page is to provide an identification aid for spring beauties (genus Claytonia) in the mountains of North Carolina. There are only two species native to North Carolina, Carolina Spring Beauty (Claytonia caroliniana) and Virginia Spring Beauty (Claytonia virginica), and their ranges overlap in the mountains.

C. caroliniana is common in rich cove and northern hardwood forests throughout the mountains and mostly found above 3,500 ft elevation, whereas C. virginica is more common in moist to rich forests in the eastern and central Piedmont. However, it can also be found in the mountain counties, usually below 3,500 ft elevation. In fact, both species may occur in very close proximity to each other, such as at New River State Park (~2,700 ft elevation) where C. virginica grows along the river trail and C. caroliniana along the adjacent forest trail.

When trying to distinguish between the two species based on morphology, it is diagnostic to get a good view of their leaves. Their flowers look pretty much identical, but they can be easily distinguished by the shape of their leaves. C. caroliniana has a broader leaf blade clearly differentiated from a petiole attaching it to the stem, whereas C. virginica has slender, grass-like leaves without a clearly differentiated petiole.


The NC range map above was colored in using data from the Vascular Plants of North Carolina website. The plant drawings are from the USDA PLANTS database and not copyrighted (original source: Britton & Brown: An illustrated flora of the northern United States, published 1913). For another comparison of the leaves of the two species, also see the Native Plants of the Carolinas and Georgia website.

Posted on November 10, 2019 00:42 by annkatrinrose annkatrinrose | 4 comments | Leave a comment

Archives

Gracias al apoyo de:

¿Quiere apoyarnos? Pregúntenos cómo escribiendo a snib.guatemala@gmail.com