The veiled species of Hebeloma in the western United States / Alexander H. Smith, Vera Stucky Evenson, and Duane H. Mitchel.

The Subgenus Hebeloma

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aline globules as revived in KOH. Pleurocystidia none. Cheilocystidia
(33) 40-62 x (6) 7-11 RLm, neck 3-5 Jm diam, fusoid-ventricose, not
agglutinating.
Lamellar and pilear tissues.-Lamellar trama in Melzer's showing
a flush of red to reddish orange along the base of the hymenium.
Cuticle of pileus a well-defined ixolattice of hyphae 2-4 [Jm diam and
with + gelatinized walls (some nongelatinized veil hyphae at times
overlaying this layer). Hypodermium cellular, the cells somewhat enlarged and pale rusty brown in KOH, incrustations (or wall thickenings) present but not conspicuous; copious dextrinoid debris present
near and in the layer. Tramal hyphae of pileus ochraceous-hyaline in
KOH, smooth, radial-interwoven, cells inflated to 12-30 pxm diam,
narrower near the gill edge. Clamp connections present.
Habit, habitat, and distribution.-Gregarious under aspen, Sam's
Knob, Snowmass Village, Pitkin County, Colorado, September 2, 1979
(type, MICH).
Observations.-In radial sections the hypoderm is seen to consist
of short to long inflated hyphal cells. In KOH the color is at first
pronounced but fades considerably in 15 minutes. Dextrinoid debris is
present in the mount variously: in the gill or pileus trama, apex of the
stipe, or occasionally in the ixolattice. The shiny reddish brown pileus,
the weak FeSO4 reaction on the base of the stipe and the habitat under
aspen distinguish this variety. H. testaceum in the sense of Bruchet has
amygdaliform spores (8) 10-12 (13) x 5-6 (6.5) Vxm.
35f. Hebeloma mesophaeum var. castaneum var. nov.
Pileus 1-2.5 (3) cm latus, obtuse conicus vel subcampanulatus,
tenuiter fibrillosus deinde glaber, ad centrum ~ castaneus demum subargillaceus; odor et gustus subraphaninus. Lamellae pallidae demum
cinnamomeae, latae, confertae adnatae. Stipes 3-4 cm longus, 3-4 mm
crassus, griseofibrillosus, brunnescens. Sporae 8.5-10 x 5-6 (m, ovoideae vel ellipsoideae, non dextrinoideae, subleves, in "KOH" ochraceae. Cheilocystidia anguste fusoid-ventricosa, 45-65 x 5-9 x 3-4 pJm.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
88922; legit prope Elk Wallow, Pitkin County, Colorado, 9 Aug 1978,
Thiers and Smith.
Pileus 1-2.5 (3) cm broad, obtusely conic expanding to broadly
conic to convex, surface glabrous over disc, thinly coated with veil
remnants on the margin, at times with inconspicuous patches; disc
chestnut brown to cinnamon-brown, margin paler and grayer, some
with a faint ochraceous flush. Context thin, watery brown, pale dingy