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

Observations.-The veil is very soon evanescent. The livercolored pileus, farinaceous taste, vinaceous-buff lamellae at first, the
darkening stipe and the + tibiiform cheilocystidia make it a very distinct species.
53. Hebeloma parcivelum sp. nov.
Illus. Figs. 30-31.
Pileus 3-7.5 cm latus, conicus demum plano-umbonatus, viscidus, ad marginem gossypinus, glabrescens, pallide argillasceus demum
brunneomaculatus; odor et gustus mitis. Lamellae avellaneae deinde
cinnamomeae, adnatae, latae, confertae. Stipes 6-8 cm longus, 8-12
mm crassus, deorsum brunnescens. Velum sparsim, pallidum. Sporae
7-10 x 5-6 Lm, subleves, dextrinoideae, inequilaterales. Cheilocystidia 20-30 x 5-6.5 pLm, filamentosa vel fusoid-ventricosa. Hypodermium pileorum nullum
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
23703; legit sub Alni, prope Waupanitia Summit, Mt. Hood, Oregon,
~ 3,000 ft elevation, 24 Sep 1946.
Pileus 3-7.5 cm broad, obtusely conic with an inrolled margin,
expanding to plano-umbonate and the margin at times wavy, surface
glabrous, slightly viscid, margin cottony at first, "Pale Pinkish Buff"
overall or disc darker and near "Cinnamon-Buff," in age developing
darker sordid brown spots. Context thick, concolorous with surface,
odor and taste none.
Lamellae broad, close, bluntly adnate, "Avellaneous" at first, in
age with a "Cinnamon" cast but always dull, edges even and not
beaded.
Stipe 6-8 cm long, 8-12 mm thick, equal, solid, pale pinkish buff
near apex, becoming dark "Saccardo's Umber" from the base upward
and finally dark bister, a very slight veil present at first, leaving the
surface somewhat fibrillose in the midportion, apical region pruinose.
Spores 7-10 x 5-6 pJm, in profile view broadly inequilateral, in
face view broadly ovate, very minutely roughened (marbled), pale
dingy ochraceous in KOH, reddish tawny in Melzer's (+ dextrinoid).
Hymenium.-Basidia 4-spored, 20-23 x 6-6.5 Jm. Pleurocystidia none. Cheilocystidia small (20-30 x 5-6.5 Vxm), ~ filamentous,
some slightly ventricose at or near the base, apparently becoming more
elongated in age.
Lamellar and pilear tissues. —Lamellar trama typical of the genus.
Cuticle of pileus an ixocutis, hyphae 2.5-4 JIm diam, walls refractive,