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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Buff," ad marginem fibrillosus vel minute squamulosus, glabrescens;
gustus leviter farinaceus, odor mitis. Lamellae pallidae deinde avellaneae demum + cinnamomeae, confertae, angustae, adnatae. Stipes 2 -4 (6) cm longus, 2-5 (8) mm crassus, lacerato-fibrillosus. Velum fibrillosum, subalbidum; stipes deorsum brunnescens. Sporae 8-10 (11) x
5-6.5 pm, subleves, ellipsoideae vel ovoideae vel phaseoliformes, non
dextrinoideae. Cheilocystidia 38-66 x 7-11 x 3-5 RLm fusoidventricosa, rare bifurcata, demum agglutinata.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
89471; legit prope Elk Camp, Burnt Mt., Pitkin County, Colorado, 14
Jul 1949.
Pileus 1.5-4 (6) cm broad, convex to obtusely campanulate, surface subviscid, brownish drab to dingy orange-cinnamon to "Sayal
Brown" (dull cinnamon) very hoary overall at first from a coating of
pallid veil fibrils, in age often covered with minute appressed squamules before becoming glabrous, opaque at all stages. Context watery
brown fading to pale buff, taste slight (faintly farinaceous), odor not
distinctive; FeSO4 on stipe base instantly blackish green, on the pileus
slowly olive.
Lamellae near avellaneous when young, becoming "Sayal
Brown," narrow, close, adnate, edges even.
Stipe 2-4 (6) cm long, 2-5 (8) mm thick, equal, rigid, ragged
from veil remnants and often with an evanescent annular zone or
simply thinly fibrillose, glabrescent, soon bister at the base and the
color change progressing upward but apex remaining pallid.
Spore deposit "Clay Color" as air-dried. Spores 8-10 (11) x 5 -6.5 Jim, appearing smooth in KOH, in Melzer's minutely punctate
under oil immersion, not dextrinoid, shape in face view ovate to elliptic, in profile elliptic to + bean-shaped.
Hymenium.-Basidia 4-spored, 7-9 Jm broad, containing numerous hyaline globules as revived in KOH. Pleurocystidia none. Cheilocystidia elongate fusoid-ventricose, 38-66 x 7-11 x 3-5 Jim, subacute
to obtuse, rarely forked at a short distance below the apex, some
present as filaments 3-5 tJm diam, hyaline at first but in age agglutinated and the masses rusty brown as revived in KOH or in Melzer's.
Gill trama typical of the genus.
Cuticle of pileus a poorly defined layer of hyphae 3-4.5 Ixm wide
with only subgelatinous walls and an outer area of veil hyphae 4-7 Jim
diam. Hypodermium a layer of rusty brown, wide hyphae appearing
cellular in tangential sections, incrustations present but inconspicuous.
Pileus trama of + radial-interwoven hyphae with inflated cells and
some dextrinoid debris present. Clamps present.
Habit, habitat, and distribution.-Densely gregarious on an out