Cap: 15-35 mm diam., convex to subumbonate or subcampanulate,
even but translucent-striate at the margin when moist, sometimes subrimose
with age. glabrous with lobed to irregular margin, subviscid, dark brown
to brownish-yellow, hygrophanous, context is pliant, whitish and thin
in the pileus and staining blue when handled.
Gills: Adnate to subadnate, dark brown-violet with whitish edges.
Stem: 50-80 x 1.5-2.5 (-4) mm. Equal, hollow, whitish to brownish or
reddish and covered with small silky whitish fibrils. Veil thin fine
silky fibrils on the stipe turning evanescent.
Spores: (5-) 6-6.5 (-7.7) x 4.9-6.5 (-7) x 3.3-4µ. Rhomboid or
subglobose in and subellipsoid in the side with a short basal appendage
and with a narrow germ pore.
Sporeprint: Purple-brown violet in deposit.
Habitat: Solitary or in small groups on humus or muddy soil in deciduous
forests of Liquidambar-Quercus at 500-1400 m elevation.
Distribution: Known only from the subtropical forests of Mexico.
Season: Fruiting in the summer months of June-August.
Comment: Pileus, stipe and context staining green-blue to blackish when bruised. This species was named in honor of French mycologist Roger Heim, who along with Dr. Wasson contributed important studies concerning the sacred mushrooms of Mexico.