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Entoloma roanense

by Michael Kuo, 29 September 2024

Droopy and drab, this little grayish brown mushroom appears in moss and leaf litter in hardwood forests. Its cap features a slightly lined margin, and in dry conditions it can become silky or even finely scaly. The gills are white at first, but become pink as the spores develop. The odor is not distinctive. The stem is colored like the cap, and features prominent white mycelium at its base. Microscopic features include 5 to 7-sided spores, a lack of cystidia, and smooth brown elements in the pileipellis.

Using Hesler's monograph for southeastern North America (1967), the collections featured here key to Entoloma roanense, which he described from Tennessee under spruce and hardwoods. Using European keys (Noordeloos 1988a, 2018), one arrives at Entoloma solstitiale, a grassland European species that is more brown and less gray, and features slightly smaller spores.

Complicating things is Noordeloos's study of Hesler's type collection (1988b); Noordeloos found that, among the four specimens in the collection, three had spores that were primarily 5-sided and "almost cuboid," while one specimen had "ellipsoid, 5–7–angled spores." Noordeloos concludes that Hesler's type "appeared to be a mixture of two taxa," and he excludes the ellipsoid-spored specimen "because it did not fit with the other specimens nor the protologue."

However, Noordeloos's illustrations of the spores in question do not agree with his text; the accepted spores are illustrated as 4-sided and cuboid, with one 5-sided exception, while the deviant spores are illustrated as 5-sided but slightly more elongated ("ellipsoid"). Additionally, Hesler's protologue is not at odds with the deviating spores; he describes the spores as "8–10 x 6–8 µ, 5-sided, at times obscurely 4–5–6-sided."

The spores of the collections illustrated and described here match Hesler's description and are primarily 5-sided and "ellipsoid," but occasionally 4-sided and cuboid. Noordeloos suggests the possibility that Hesler's Entoloma roanense is the same as Entoloma solstitiale, but he stops short of synonymizing the species. Europe's recently named Entoloma incognitum is also similar (the epithet incognitum refers to its incognito history, since it was included in Entoloma solstitiale).

Thanks to Michelle Lierl for collecting, documenting, and preserving Entoloma roanense for study; her collection is deposited in The Herbarium of Michael Kuo.

Description:

Ecology: Saprobic; growing alone or gregariously under hardwoods; summer; originally described from Tennessee (Hesler 1967); distribution uncertain, but possibly to be expected throughout eastern North America. The illustrated and described collections are from Illinois and Indiana.

Cap: 1–3 cm across; convex to broadly conic or broadly bell-shaped; often developing a tiny central depression; finely silky, becoming fibrillose or minutely scaly in age or dry weather; dry; the margin lined at maturity and sometimes splitting radially; grayish brown, often with a darker brown spot over the disc.

Gills: Narrowly attached to the stem; close; short-gills frequent; white, becoming pink as spores mature.

Stem: 4–7 cm long; 1–3 mm thick; equal above a slight basal swelling; dry; bald; grayish brown to brown; basal mycelium white and prominent.

Flesh: Whitish; unchanging when sliced.

Odor and Taste: Odor not distinctive; taste slightly bitter.

Chemical Reactions: KOH negative on cap surface.

Spore Print: Pink.

Microscopic Features: Spores 8–12 x 6–8 µm; angular; predominantly 5-sided, but not infrequently 4-, 6-, or 7-sided; ellipsoid overall, with a large apiculus; smooth; thin-walled; hyaline in KOH or ammonia; inamyloid. Basidia 28–32 x 6–11 µm; clavate; 4-sterigmate. Hymenial cystidia not found. Pileipellis a cutis; elements 3–10 µm wide, smooth, brown in KOH or ammonia; clamp connections not found.

REFERENCES: L. R. Hesler, 1967. (Hesler, 1967; Noordeloos, 1988a; Noordeloos, 1988b; McNeil, 2006; Noordeloos, 2018; Reschke et al., 2022.) Herb. Kuo 07140304, 06161003, 07191603, 06082403.

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Spore print

Spores

Pileipellis

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Cite this page as:

Kuo, M. (2024, September). Entoloma roanense. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/entoloma_roanense.html