Hohenbuehelia in NZ

I've had a long-standing interest in our Pleurotoid fungi, of which Hohenbuehelia is one genus. They are mostly brown or grey and the larger species can look very much like Pleurotus but are easily distinguished microscopically by the presence of large thick walled cystidia on the gills (metuloids) usually encrusted with crystals. They also have smaller strangulate-looking cystidia which are associated with drops of mucilage toxic to nematodes (called gloeosphex cystidia). Greta Stevenson named most of our species back in the 1960's but the associated descriptions focused on macro-morphology and are of limited use. Some keys for the group elsewhere have used characters such as fruitbody shape (fan-shaped or tongue shaped) but these can be variable. I have revised the type collections, combined with more recent collections, many of them sequenced and compared with existing material from overseas. It turns out the most diagnostic characters are the spores size and shape, combined with the appearance of the dark-brown pilocystidia which occur (sometimes sparsely) in the gelatinised cap tissue. This work, and the associated sequencing, has thrown up some surprises.

The undescribed H. 'Ahurirri' is a centrally stipitate species. It's affiliation with Hohenbuehelia is obvious from the presence of both metuloid and gloeosphex cystidia. Stipitate forms are rare in the genus and H. 'Ahurriri' occurs basal to the Hohenbuehelia clade and is suggestive of an ancestral form.

Hohenbuehelia ligulata (long known as Panellus ligulatus) is an orange tongue shaped species without metuloids, but the presence of gloeosphex cystidia clearly indicated, even before it was sequenced, that it belonged in Hohenbuehelia. It may also be the same as the Australian species Dictyolus cinamoneus but recent collections of that require critical comparison with Cleland's type.

H. bonii was only recently described in association with Marram grass in the UK. It has historically been misidentified as another marram-associated species called H. culmicola. In NZ we have one collection from Dunedin dunes, which is clearly this species both morphologically and phylogenetically (PDD 87504). However, work remains to be done on this group. One Canadian sequence of Nematoctonus leiosporus is also identical to H. bonii (and others with that name are close). Nematoctonus is the name given to the anamorph nematode-trapping state of Hohenbuehelia. The relationship between N. leiosporus and H. bonii needs clarification, especially as we have another ‘species’ with identical sequences to H. bonii and the Canadian N. leiosporus which is yellowish (like H. luteola) and grows on wood, not Marram (PDD 95515) and for which I retain the name H. leiosporus (without any particular justification!).

H. cyphelliformis is a distinct small grey species usually on living shrubs like Sophora. It is rare in the northern hemisphere but common here.

H. brunnea is very common and Greta described and the same species under the name H. podocarpinea. The two names point to its morphological variability. Sequenced New Zealand collections are very close to H. grisea (recently inappropriately neotypified by a collection from Austria, when the original type comes from New York!). It is likely that H. grisea provides an earlier name, when the correct application of that name has been confirmed.

Stevenson also described a species called Tectella luteola (with a veil that turned out so be a parasitic fungus) that is identical (somewhat confusingly) to a species she named H. luteola in the same paper, and H. luteohinnulea, also in the same paper. The correct name is H. luteola, and, as the name suggest it is yellowish (and can look like H. leiospora).

H. tristis is insufficiently known at present. Egon Horak considered it to be a synonym of H. nothofaginea but further collections are required.

Finally, H. parsonsiae is part of the globally distributed H. petalodes complex and phylogenetic data suggests multiple species in this complex, perhaps even within NZ. H. parsonsiae is sufficiently distinct to be considered a separate species. H. parsonsiae, like H. petalodes can be found growing in soil with wood chips, as well as on rotten wood.

Key to NZ species of Hohenbuehelia (see NZFUNGI2 website for collections/images)

1 - Fruitbody centrally stipitate- H. sp. ‘Ahurriri’
1’- Fruitbody laterally attached, with or without a pseudostipe- 2

2 - Fruitbody ligulate, orange to cinnamon coloured, without metuloids- H. ligulatus
2’- Fruitbody brown, grey, yellow, tan, brown, with metuloids- 3

3 - Spores ellipsoid, Q less than 1.6. Frb usually with rhizoids- 4
3’- Spores cylindrical to allantoid, Q over 1.8. Frb usually without rhizoids- 7

4 - Spores greater than 8um long, pilocystidia wall less than 2um at thickest- 5
4’- Spores less than 7um long, pilocystidia wall over 3um at thickest, Cap yellow, tan, or dark brown.- 6

5 - Cap yellow, on wood- H. leiospora
5'- Cap brown, with marram grass- H. bonni

6 - Cap yellowish, often with olivaceous hues. Cap vertical section without dark brown band. Pilocystidia sinuate, pale.-H. luteola
6’- Cap chestnut brown, polished. Cap vertical section with dark band(s). Pilocystidia dark brown, setoid. [If cap with scale-like tufts see H. sp. PDD 87277 (JAC1087)]- H. parsonsiae

7 - Cap grey, gills brilliant white, spores allantoid, metuloids hardly projecting. Frb laterally attached, without pseudostipe.- H. cyphelliformis
7’- Cap grey to brown, gills cream to orange, spores cylindrical, metuloids distinctly projecting. Frb. Laterallay attached or with lateral pseudostipe.- 8

8 - Cap without pilocystidia (species known only from type)- H. tristis
8’- Cap with pilocystidia- 9

9 - Cap dark brown, usually with lateral pseudostipe, gills yellow/orange with age- H. nothofaginea
9’- Cap grey to tan, laterally attached, without pseudostipe. gills remaining pale- H. brunnea

Posted on July 04, 2016 12:15 AM by cooperj cooperj


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