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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Stipe 3-4.5 cm long, 3-4 mm thick, equal, soon hollow, fragile,
pallid at first but soon darkening to bister from the base up, somewhat
fibrillose from the grayish veil but no annular zone evident when it
breaks.
Spore deposit as air-dried about "Sayal Brown"; spores (8) 9-11
x 5-6 rim, pale clay color in KOH, paler in Melzer's (not dextrinoid),
obscurely mottled (as seen mounted in Melzer's), somewhat beanshaped to obscurely inequilateral in profile, elliptic to ovate in face
view, apex obtuse.
Hymenium.-Basidia 4-spored, 8-9 Jim broad. Pleurocystidia
none. Cheilocystidia abundant (46) 57-86 x 7-15 x 3.5-5 pum, fusoidventricose, the neck slightly tapered to a subacute to obtuse apex,
flexuous; hyaline, smooth, wall not appreciably refractive.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus a poorly defined ixocutis, the hyphae 2-3.5 Jxm
wide, only slightly gelatinous, clamped, smooth to slightly encrusted.
Hypodermium "cellular" (in tangential sections), cell walls in KOH
rusty brown (about the same in Melzer's), incrustations and/or wall
thickenings numerous. Tramal hyphae typical of the genus (not with
red content as mounted in Melzer's).
Habit, habitat, and distribution.-Densely gregarious on soil, Fryingpan River, Pitkin County, Colorado, above Elk Wallow, July 30,
1978 (type, MICH).
Observations.-The grayish veil and a + distinctly pungent taste
and odor distinguish this variety from var. mesophaeum. Other differences such as the squamulose pileus margin at first, and an appreciable
number of very large cheilocystidia along with a larger number of
spores bean-shaped in profile view, will be noted.
35j. Hebeloma mesophaeum var. fluviatile var. nov.
Pileus 1.5-4 cm latus convexus demum campanulatus, subviscidus, griseobrunneus demum sordide cinnamomeus, canescens demum
nudus. Odor debilis (+ raphaninus). Lamellae confertae, angustae,
adnatae, avellaneae demum sordide cinnamomeae. Stipes 2-4 (6) cm
longus, 2-5 mm crassus, strictius, fibrillosus, deorsum demum triste
spadiceus. Sporae 8-10.5 x 5-6 Rxm, non dextrinoideae. Cheilocystidia
38-54 x 7-11 x 3-5 lim, fusoid-ventricosa. Cuticula pileorum subixocutis est. Hypodermium in "KOH" fulvobrunneum.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
89471; legit prope Elk Camp, Burnt Mt., Pitkin County, Colorado, 14
Jul 1979.