Subulicystidium brachysporum (P.H.B. Talbot & V.C. Green) Jülich
The genus Subulicystidium is characterized by amazing subulate (tapering to a point) cystidia with rectangular crystals that encircle the cystidia in rows or spirals. And poking out of the top of each cystidium is a hypha, which runs through the center of the barb-like structure. Who knows the adaptive function of these strange microscopic structures, but to me they look like they are for defensive purposes, perhaps against the many animals that graze on crusts.
Subulicystidium consists of 24 species (Liu et al. 2022).
Subulicystidium brachysporum is a somewhat ambiguous taxon. Many sequences with high divergence share this name in GenBank, suggesting this is a species complex that needs to be disentangled.
Details
Ecology:
White, effused, resupinate basidioma with a smooth hymenophore.
Not determined.
Not determined.
Not determined.
Currently only known from a single sequenced collection from Wisconsin. View all sequenced specimens on iNaturalist.
Microscopy
Hyphal system: Monomitic, encrusted, subicular hyphae somewhat thick-walled, clamped, width (3.6) 3.9–5.1 (5.3) µm, x̄ = 4.5 µm (n = 10). Basidia: Repetitive basidia with four sterigmata, about 15 ✕ 5 µm. Basidiospores: Narrowly cylindrical to allantoid, thin-walled, hyaline, inamyloid; length (6.4) 7.5–8.8 (9.4) µm, width (2.2) 2.5–2.9 (3.2) µm, x̄ = 8.2 ✕ 2.7, Q (2.1) 2.7–3.3 (3.5); biguttulate (two equally sized oil droplets situated at the poles of the spore), rarely one or three guttules, diameter (1.2) 1.3-1.6 (1.6) µm (n = 30). Sterile structures: Subulicystidia.
Studied Specimens
UWMA0061 (iNat172305516). 23 June 2018. University of Wisconsin Arboretum, Dane Co., WI, USA, 43.0563 -89.4055. Kriebel Fungarium (PUL00047282). Sequences: MW448634 (ITS).
References
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Liu S, He S, Wang X, May T, He G, Chen S, Zhou L. 2022. Trechisporales emended with a segregation of Sistotremastrales ord. nov. (Basidiomycota). Mycosphere 13:862–954. PDF Link
Citation
Dirks, Alden. 2026. Species profile for Subulicystidium brachysporum (P.H.B. Talbot & V.C. Green) Jülich. CrustFungi.Com. https://crustfungi.com/species/subulicystidium-brachysporum/. Accessed 2026-01-16.