Simocybe centunculus
What You Should Know
Simocybe centunculus is a widespread mushroom in North America. This small, inconspicuous mushroom includes an olive-brown, often velvety appearing, striate-margined cap, and hardwood habit.
Older specimens tend to have more brownish caps with less obvious striations but usually can be identified by confirming with a hand lens the presence of a "cellular-like" cuticle and fringed gill edges.
Other names: Dingy Twiglet, American Simocybe.
Simocybe centunculus Mushroom Identification
Cap
Pileus 1.0-2.5 cm broad, convex, expanding to nearly plane; margin incurved, decurved at maturity; surface when young, minutely pruinose to velvety, olive-brown, the margin paler, translucent striate, hygrophanous, in age opaque, ochre-brown to dull-brown; context thin, olive-brown.
Lamellae
Gills adnate, close, relatively broad, olive-brown, the edges fringed; lamellulae up to three-seried.
Stipe
Stipe 1.5-3.0 cm long, 2.0-4.0 mm thick, equal, hollow, straight or curved; surface when young, pubescent, the ornamentation white over an olivaceous or dull-brown background, nearly glabrous in age, white mycelium at the base; partial veil absent.
Spores
Spores 6.0-8.0 x 4.0-5.0 µm, ellipsoid to ovoid in face view, bean-shaped inside view, smooth, hilar appendage not conspicuous; spore print olive-brown to brown.
Flesh
Insubstantial.
Odor and Taste
Odor not distinctive or slightly unpleasant to spermatic.
Chemical Reactions
KOH red on cap surface.
Microscopic Features
Spores 6-8 x 4-5 µ; smooth; mostly kidney-shaped but a fair number deviating to subglobose, sublacrymoid, or subelliptical; dingy yellowish in KOH or Melzer's reagent. Basidia clavate; 4-sterigmate. Pleurocystidia absent. Cheilocystidia abundant to scattered; cylindrical to cylindrico-clavate; up to 60 x 6 µ. Pileipellis a densely interwoven trichoderm with inflated terminal elements (a "hymeniform layer") embedded in poorly defined material, with frequent (in young caps) to scattered bundles of subcylindric to subfusiform, cystidium-like elements with rounded apices projecting up to 60 µ.
Habitat
Solitary to clustered on well-rotted hardwood logs; fruiting early in the mushroom season.
Sources:
Photo 1 - Author: Parande (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 2 - Author: Dan Molter (shroomydan) (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 3 - Author: Dan Molter (shroomydan) (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 4 - Author: Sava Krstic (sava) (Creative Commons Attribution-Share Alike 3.0 Unported)
