The veiled species of Hebeloma in the western United States / Alexander H. Smith, Vera Stucky Evenson, and Duane H. Mitchel.

150

The Veiled Species of Hebeloma

lens, dingy pallid clay color in KOH, pale reddish tawny in Melzer's
(slightly dextrinoid).
Hymenium.-Basidia 4-spored, 23-26 x 7-12 pIm, hyaline in
KOH. Pleurocystidia none. Cheilocystidia 34-50 (60) x 7-12 x 3-5
ILm, fusoid-ventricose, apex obtuse, hyaline, smooth, thin-walled.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus of subgelatinous hyphae 3.5-6 pIm diam, hyaline
and appressed (forming a "subixocutis"). Hypodermium cellular, the
cell walls bister or darker in KOH. Tramal hyphae typical of the genus. Clamps present.
Habit, habitat, and distribution.-Gregarious to scattered on humus in an open area, Frog Lake, Mt. Hood National Forest, Oregon,
October 8, 1946 (type, MICH).
Observations.-The narrow, hollow, fragile brunnescent stipe,
scarcely viscid pileus, and raphanoid odor and taste, are its major
characters in addition to those of the spores.
H. marginatulum Bruchet differs in not having a strongly raphanoid odor and taste. It does have more distinctly ornamented, thickwalled spores, but only a thin cortina. The stipe in H. oregonense is
fibrillose from the veil and the latter is buff in color. Bruchet illustrates
a stipe for H. marginatulum which in some basidiocarps is narrowed at
the base almost to the degree of producing a short pseudorhiza.
H. oregonense is close to H. clavulipes Romag. but has an equal
stipe and a colored veil. The two, however, clearly belong in the same
stirps.
85b. Hebeloma oregonense var. atrobrunneum var. nov.
Pileus 2-3.5 cm latus, obtusus vel late convexus, canescens demum glaber, viscidus, atrobrunneus. Contextus brunneus demum griseoochraceus, odor pungens, gustus mitis. Lamellae latae, ventricosae,
demum subdistantes, pallidae dein "Verona Brown" (rufobrunneae).
Stipes 2.5-4 cm longus, 3-6 mm crassus, brunnescens. Velum fibrillosum, griseoochraceum. Sporae 11-14 x 7-8.5,xm, inequilaterales,
non dextrinoideae. Basidia tetraspora, 8-10 txm crassa. Cheilocystidia
42-60 x 7-11 x 6-7 Vxm, cylindrica vel fusoide ventricosa.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
89268; legit prope Elk Camp, Burnt Mt., Pitkin County, Colorado, 2
Sep 1978.
Pileus 2-3.5 cm broad, obtuse to convex or at times the margin
uplifted, hoary at first, the disc blackish brown beneath the canescence, marginal area slowly becoming dull reddish brown, margin at
first faintly decorated with veil fibrils. Context brown fading to grayish