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

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The Veiled Species of Hebeloma

As illustrated by Lange (1938) it is extremely light. Our observations
to date support this. Also, the FeSO4 reaction on the base of the stipe
should be checked on more mature specimens. The cheilocystidia indicate a relationship to members of subgenus Denudata in that most of
them are greatly elongated and have an enlarged though not capitate
apex. The aspect of the fruiting bodies in the field is that of H. pascuense but the inequilateral spores in profile view clearly distinguish it.
H. piceicola has a dingy buff veil and cheilocystidia having relatively
unenlarged apices. Lange's (1938) account covers our specimens rather
well. As shown, the stipes are essentially equal and the change to
brown in the lower portion is not very conspicuous. The variation in
the cheilocystidia, however, deserves further study.
90. Hebeloma pitkinense sp. nov.
Pileus 2-4 cm latus, plano-depressus, viscidus, ad marginem fibrillosus, glabrescens, pallide spadiceus vel fuscospadiceus; odor et
gustus mitis. Lamellae pallidae demum pallide alutaceae vel sordide
cinnamomeae, latae confertae. Stipes 4-7 cm longus, 4-5 mm crassus,
brunnescens. Velum fibrillosum, alutaceum. Sporae 9-12 x 6-7.5 JIm,
punctatae, in "KOH" argillaceae. Basidia tetraspora, ad apicem 9-11
jLm lata. Cheilocystidia 33-52 x 7-9 Jpm, deorsum subventricosa.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
86865; legit prope Snowmass Village, Pitkin County, Colorado, 18 Jul
1976.
Pileus 2-4 cm broad, plano-depressed and margin typically
arched slightly, surface viscid, at first the marginal area decorated with
patches of pallid veil fibrils, glabrescent; color a pale date brown to
"Saccardo's Umber," margin virgate in age in one pileus. Context dark
butterscotch color when moist, near cinnamon-buff when faded, soft,
fragile, thin, odor and taste not distinctive, FeSO4 quickly dark green
on the lower part of the stipe, less so in the pileus, KOH no reaction.
Lamellae broad, close, adnate, equal or in age broadest near
pileus margin, pallid then + pinkish buff and finally dark dull cinnamon, thin, edges even, not beaded or spotted.
Stipe 4-7 cm long, 4-5 mm thick, equal, tubular, dull brown
within, darkening from the base upward, surface fibrillose from the
veil, + glabrescent, fibrils brownish; surface of stipe fibrillose-striate,
grayish pallid at or near the apex.
Spores 9-12 x 6-7.5 rLm, minutely punctate, clay color in KOH,
ovate in face view, obscurely inequilateral in profile or ventral line
straight and dorsal line (in optical section) convex.
Hymenium.-Basidia 4-spored, 9-11 Vm broad near apex. Pleu