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

Pileus 1.5-4 cm broad, convex expanding to plane or the margin
decurved, margin finally spreading or uplifted, sometimes wavy, color
"Prout's Brown" to "Cinnamon-Brown," gradually paler, the margin
brownish gray in age, fading overall to + alutaceous, subviscid, soon
glabrous. Context pallid when faded, odor pungent, taste mild, FeSO4
instantly staining the base of the stipe blackish.
Lamellae broad, close, adnate, avellaneous when young + clay
color in age, not beaded and not staining.
Stipe 2.5-4 cm long, 4-6 (9) mm thick at apex (flared at times),
silky, becoming dark brown from base upward; veil material cinnamonbuff, distributed in small patches on lower half; silky near apex (not
pruinose), upper half usually pallid.
Spore deposit dull clay color. Spores 10-13 x 6-7.2 pjm, dull
ochraceous in KOH, pale reddish tan in Melzer's; shape in profile
inequilateral, ovate to boat-shaped in face view, surface faintly marbled (under a high-dry objective); apex + snoutlike on the larger
spores, wall not truly dextrinoid.
Hymenium.-Basidia 4-spored, 8-10 pxm broad, projecting 10-15
pxm when sporulating. Pleurocystidia none. Cheilocystidia 36-54 x 5-6
x 10-15 pIm slightly ventricose near the base, apex obtuse, agglutinated in age.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus a poorly developed ixocutis of hyaline appressed
refractive hyphae 2.5-3.5 jim diam, clamps present. Hypodermium
cellular to hyphoid, tawny in KOH and reddish tawny in Melzer's,
dextrinoid debris present in places in the hypodermium, the pilear and
the lamellar trama. Tramal hyphae not red as revived in Melzer's.
Habit, habitat, and distribution.-Gregarious under spruce and
fir, above Snowmass Village, Pitkin County, Colorado, August 16,
1978 (type, MICH).
Observations.-For a comparison with H. corrugatum see that
species. H. pallescens shows an exceptional amount of dextrinoid debris in its tissues but the spores are not distinctly dextrinoid. It appears
to be close to H. oregonense var. atrobrunneum.
Stirps OREGONENSE
Spores not dextrinoid.
KEY TO SPECIES
1. Taste and usually the odor of the crushed context raphanoid................. 2
1. Not as above (odor + pungent in some and in others the taste
farinaceous to bitter or at least not raphanoid).............................. 9
2. Spores 9-12 Jim long................................................ 3
2. Spores (10) 12-15 pim or more long................................... 5