E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Subgenus Phlegmacium (but note non-viscid cap). Features include a non-viscid, brown, tomentose cap, whitish young gills, a white, club-shaped stem, a whitish veil, and large cystidia. According to Kernaghan(1) North American material as described by Smith differs from European material in lacking filiform cystidia.

Smith found Cortinarius crassus in WA and says "frequently collected in our western mountains" (Smith(6)). Phillips(1) says it is found in the Pacific Northwest, in CO and other parts of the Rockies, and in the Great Lakes region. Stuntz(5) says it is not common in WA. Kernaghan(1) reported it from western AB (sensu Smith). A Paul Kroeger collection from BC is deposited at University of British Columbia. It is also found in Europe.

Cap:
4-10cm across, (hemi-)spheric, then flat-convex; "rarely slightly hygrophanous, homogeneous pale leather-brown, ochraceous brown to darker, almost red-brown"; "distinctly (innately) fibrillose to tomentose", (Brandrud), 5-12cm across, tobacco- to hazelnut-brown; "completely dry, also young, almost tomentous", (Moser), soon dry (Phillips), tomentose (Hansen), 10-12cm, convex to nearly flat; "clay color" on disc at first, margin paler and buff, becoming darker when old ("russet" to "cinnamon-brown"); viscid when wet, pellicle scarcely separable, bald or at first streaked with fibrils on the margin, when old appressed or agglutinated-fibrillose under a lens, the fibrils sometimes in patches on the disc causing a subscaly appearance, (Smith(22)), 10-12.5cm across, slimy when wet, with fibrillose streaks and sometimes also spot-like patches beneath slime layer, (Stuntz)

Flesh:
whitish with ochraceous yellow hygrophanous streaks in stem when young, (Brandrud); thick, white; compact; in stem sordid brownish, (Smith(22))

Gills:
crowded, narrow; "initially (ochraceous) white, persistently pale"; somewhat fimbriate at edge, (Brandrud), clay-brown, edges lighter, (Moser), adnexed, close, broad; white at first, dark cinnamon brown when old, (Smith(22)), adnexed; pallid buff at first then cinnamon brown (Phillips)

Stem:
4-11cm x 1-2.5cm, club-shaped at base (up to 3cm wide) and often somewhat radicating [rooting]; white; frequently with abundant, cottony basal mycelium, (Brandrud), 5-8cm x 1.5-3cm, pale, browning in places, (Moser), 8-13cm x 1.2-1.5cm, equal or narrowed in lower part, solid; white at top, sordid brownish in lower part; dry, at top silky, in lower part fibrillose, (Smith(22)), 5-8cm x 1.5-4cm, equal; whitish; fibrillose, (Phillips), 10-12.5cm x 1.8-3cm, (Stuntz)

Veil:
"sparse and fibrillose, white to faintly ochraceous", (Brandrud)

Odor:
indistinct (Brandrud, Smith(22))

Taste:
mild (Phillips)

Microscopic spores:
spores 7-9 x 3.5-4.5 microns, elliptic to amygdaliform (with somewhat irregular wall), faintly verrucose, pale; gill edge normally with conspicuous, irregularly cylindric to clavate cheilocystidia (40-70(90) x 5-8 microns), pleurocystidia similar; cap cuticle with a thick epicutis of (3)4-7 microns wide hyphae, basally up to 12 microns (hypodermium-like) wide elements, usually with distinct zebra-striped encrustations, (Brandrud), spores 7.5-10 x 4.2-5 microns, (Moser), spores 9-11(12) x 5-6 microns, narrowly oval to somewhat almond-shaped, dark rusty brown; "cystidia not differentiated", (Smith(22)), spores 10-11.6 x 6-6.7 microns, lemon-shaped, lightly roughened (Phillips), large cystidia present according to Joseph Ammirati (pers. comm.), Hansen, L.(2) says irregular +/- filiform pleurocystidia and cheilocystidia, Moser(1) gives cheilocystidia 40-80 x 3-9 microns, Breitenbach(5) says pleurocystidia similar to cheilocystidia and abundant, cheilocystidia abundant, 25-80 x 7-9 microns, polymorphic, flexuous [wavy], sometimes rostrate, more rarely somewhat forked, with yellowish amorphous contents

Spore deposit:
rusty brown (Phillips)