Neohygrocybe ovina
[ Basidiomycota > Agaricales > Hygrophoraceae > Neohygrocybe . . . ]
by Michael Kuo
There are not a lot of black waxy caps, and this one is pretty unmistakable. Its black cap and stem are dry, and its pale grayish gills bruise slowly pink to red when fresh. The odor of fresh specimens is also distinctive, though it is variously described in the literature; I wrote "sweet and a little funky, fairly strong" in my journal. Neohygrocybe ovina is found in Europe, and North American versions of it appear in the eastern United States and in California (though I think the California version is a stretch, based on online photos).
A similar species, Neohygrocybe subovina, may deserve recognition; it was originally described from Tennessee (Hesler & Smith 1963) as a species "close to H. ovinus, differing in its globose to subglobose spores, and in the presence of cystidia on the gills." According to some authors Neohygrocybe subovina can also be separated from Neohygrocybe ovina on the basis of its odor, since the odor of the latter is described in European treatments as unpleasant and nitrous. Contemporary, DNA-based study of North American collections is needed to sort out precisely what our species are.
Hygrophorus ovinus and Hygrocybe ovinus, and Hygrocybe nitiosa are synonyms.
Thanks to Sherwood Forest Friends for facilitating collection of specimens.
Description:
Ecology: Precise ecological role uncertain (see Lodge and collaborators, 2013); growing scattered to gregariously in mixed hardwood/conifer woods; summer and fall; Europe, and in North America reported from the eastern United States (primarily the southern Appalachians) and, perhaps erroneously, from California. The illustrated and described collection is from North Carolina.
Cap: 2–5 cm across; convex at first, expanding to broadly convex or broadly bell-shaped; bald; moist when fresh but not sticky—and soon dry; dark gray to black, subhygrophanous and fading somewhat to medium gray; the margin not lined.
Gills: Narrowly attached to the stem; nearly distant; short-gills frequent; pale gray, bruising pink to dark red when fresh; eventually developing black discolorations.
Stem: 4–8 cm long; 0.5–1.5 cm thick; equal; bald and shiny; dry; black to gray; becoming hollow; basal mycelium whitish.
Flesh: Black to gray; unchanging when sliced.
Odor: Strong; sweet.
Chemical Reactions: KOH negative on cap surface.
Spore Print: White.
Microscopic Features: Spores 7–10 x 4–5 µm; ellipsoid to sublacrymoid; smooth; hyaline in KOH; inamyloid. Basidia 4-sterigmate. Hymenial cystidia not found. Lamellar trama parallel. Pileipellis a cutis; elements 5–15 µm wide, smooth, brownish-walled in KOH. Clamp connections not found.
REFERENCES: (Bulliard, 1793) Herink, 1958. (Hesler & Smith, 1963; Smith, Smith & Weber, 1979; Largent, 1985; Breitenbach & Kränzlin, 1991; Boertmann, 2000; Boertmann, 2008; Bessette et al., 2012; Lodge et al., 2013; Baroni, 2017.) Herb. Kuo 08091914.
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