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

100

The Veiled Species of Hebeloma

Pileus 3-4.5 cm broad, convex becoming plane with the margin
spreading and more or less wavy, margin inrolled at first and then
minutely tomentose, marginal area decorated with evanescent patches
of fibrils representing the remains of a thin fibrillose veil; color "Verona Brown" on the disc, margin "Avellaneous" and somewhat zoned,
becoming paler in age. Context concolorous with pileus, thick, odor
and taste not distinctive.
Lamellae "Avellaneous" at first (pinkish gray), soon "Army
Brown" and with a glaucous tinge in age, broad, crowded, adnexed.
Stipe 5-7 cm long, 4-8 mm thick, equal, stuffed then hollow,
pallid grayish and appressed fibrillose, apical region faintly pruinose,
becoming bister from the base upward in age.
Spores 7-9 x 4.5-5.5 pIm, in profile view inequilateral, ovate in
face view, very minutely marbled, pallid in KOH, not dextrinoid (pale
ochraceous in Melzer's).
Hymenium.-Basidia 4-spored, 23-26 x 5-6 xLm. Pleurocystidia
none. Cheilocystidia fusoid-ventricose with greatly elongated necks
and the apex obtuse, 40-60 x 6-9 x 3-4 (5) Vxm, thin-walled, wall in
neck often flexuous, hyaline in KOH.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus an ixocutis, the hyphae 2-3 pxm diam, interwoven (possibly originating as an ixotrichodermium), walls refractive
in KOH mounts. Hypodermium hyphoid, dingy brownish in KOH.
Clamp connections present.
Habit, habitat, and distribution.-Gregarious under fir on moss,
Crescent City, California, November 22, 1937 (type, MICH).
Observations.-The combination of small spores inequilateral in
profile view, darkening stipe, thin pale gray veil, and hyphoid hypoderm together appear distinctive.
48. Hebeloma amarellum sp. nov.
Illus. Figs. 34-35.
Pileus 3-7.5 latus, late convexus, glaber, viscidus, rufocinnamomeus, ad marginem albofibrillosus. Velum sparsim. Lamellae confertae vel subdistantes, adnatae, demum obscure vinaceobrunneae. Stipes
3-6 cm longus, 4-9 mm crassus, sursum albidus, deorsum demum
"Bister" (sordide spadiceus), sursum squamulosus, deorsum fibrillosus, glabrescens. Sporae 7-9 x 4.5-5 Jim, dextrinoideae, subleves, in
"KOH" argillaceae, inequilaterales. Cheilocystidia 18-30 x 3.5-6 J(m,
filamentosa vel fusoid-ventricosa. In pratis in stercore vaccino.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
9339; legit prope Crescent City, California, 3 Dec 1937.