Agaricus leptocaulis
Description
Agaricus leptocaulis is similar to Agaricus pocillator and Agaricus placomyces—but the former species features a cup-like bulb at the base of the stem and the latter species has a thicker stem. Like most species in the Xanthodermatei section of Agaricus, Agaricus leptocaulis stains yellow and features yellow flesh at the base of the stem.
Mushroom Identification
Ecology
Saprobic; growing alone or gregariously under hardwoods and conifers in forests; summer and fall; the southeastern United States, north to the southern Appalachians.
Cap
3–9 cm; convex at first, becoming broadly convex or flat in age; dry; creamy-white with a dark brown center; often becoming finely fibrillose; in wet weather sometimes developing pink shades.
Gills
Free from the stem; crowded; short-gills frequent; white, becoming pink, then brown; when young covered by a rubbery, whitish partial veil.
Stem
7–13 cm long; 0.5–1 cm thick; more or less equal above a bulbous base; bulb usually small and abrupt; whitish, bruising yellow; sometimes pinkish toward the apex; with a thick whitish ring; basal mycelium white and often prominent.
Flesh
White throughout; staining bright yellow in the base.
Odor and Taste
Odor phenolic or not distinctive.
Chemical Reactions
KOH yellow on cap surface.
Spore Print
Brown.
Microscopic Features
Spores 5–6 x 3–4 µm; more or less ellipsoid; smooth; thick-walled; brown in KOH. Basidia 4-sterigmate. Cheilocystidia 20–25 x 6–10 µm; clavate to subglobose; septate; smooth; thin-walled; hyaline to brownish in KOH. Pileipellis a cutis; elements 2.5–7.5 µ wide, smooth, golden brown in KOH.
Photo sources:
Photo 1 - Author: wearethechampignons (Public Domain)
Photo 2 - Author: sarahduhon (CC BY 4.0)
Photo 3 - Author: pufferchung (CC BY 4.0)