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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grayish fibrils, soon dark brown overall to (finally) blackish and with
only faint traces of the veil.
Spores 8-10 (11) x 5-6 iLm, yellowish in KOH, nearly hyaline
revived in Melzer's (not dextrinoid), faintly marbled, mostly oblong to
ellipsoid, in profile view a very small number obscurely inequilateral.
Hymenium.-Basidia 4-spored, 7-8 Vxm broad. Pleurocystidia absent. Cheilocystidia versiform: utriform and 18-26 x 8-11 (m, clavate
and 18-27 x 8-15 JIm, elongate-fusoid-ventricose and 36-40 x 8-11
x 4-6 [jm, and finally some elongate-clavate and + 50 x 6-8 (Jm.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus an ixocutis fairly well developed, the hyphae
2.5-4 tim diam, walls refractive (gelatinized), clamps present. Hypodermium intermediate in type (a mixture of hyphal segments and cells)
walls of the elements heavily encrusted and rusty ochraceous in KOH,
redder brown in Melzer's. Tramal hyphae typical for the genus but
with a tendency toward having encrusted walls especially near the
hypodermium.
Habit, habitat, and distribution.-Gregarious on wet earth, Independence Pass area, Pitkin County, Colorado, July 23, 1978 (type,
MICH).
20. Hebeloma nigromaculatum sp. nov.
Illus. Figs. 15-16.
Pileus (1.5) 2-4 cm latus, obtusus deinde convexus vel umbonatus, viscidus, ad marginem fibrillosus, subspadiceus deinde atromaculatus; odor et gustus raphaninus. Lamellae brunneolae deinde griseobrunneae, demum fulvomaculatae, confertae, latae, adnatae. Stipes
3-5 cm longus, 2.5-4 mm crassus, brunnescens. Velum pallidum, fibrillosum. Sporae 8-11 x 5-6 pm, non dextrinoideae. Cheilocystidia
50-80 x 8-11 x 4.5-7 pm, fusoide ventricosa, ad apicem obtusa.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
19314; legit prope Rhododendron, Oregon, 1 Oct 1944.
Pileus (1.5) 2-4 cm broad, obtuse to convex with an inrolled
margin, becoming plane or with a very slight umbo, surface viscid at
first, fringed with pallid veil remnants or veil leaving a zone of patches
near the margin, in age + glabrescent, color evenly "Tawny-Olive"
(dingy yellow-brown), in age developing blackish stains, margin often
slightly paler than the disc. Context concolor with surface, bister in
age, odor and taste raphanoid.
Lamellae moderately broad (15 mm) and close, slightly depressed
around the stipe at maturity, pallid brownish when young, near "Wood