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

98

The Veiled Species of Hebeloma

surface minutely marbled, shape in profile view inequilateral, in face
view ovate, apex blunt.
Hymenium.-Basidia 4-spored, 6-7 pxm wide near apex. Pleurocystidia none. Cheilocystidia very small, 12-22 x 3-6 x 1.5-2.5 x 3-4
Jm, ventricose near base, neck narrow and with a slight apical capitellum, hyaline.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus a well-developed ixotrichodermium collapsing to
an ixolattice, the hyphae about 1 Lxm in diam, clamped, hyaline, refractive, often branched. Hypodermium hyphoid, delimited as a +
clay-colored zone (in KOH mounts), redder in Melzer's and dextrinoid
debris evident. Tramal hyphae typical of the genus.
Habit, habitat, and distribution.-In a mixed conifer-hardwood
forest, Grants Pass, Oregon, November 11, 1956 (type, MICH).
Observations.-The important features of this species are the
bitter-farinaceous taste, the dull orange-brown pileus when fresh, the
small + tibiiform cheilocystidia, small spores and the ixotrichodermium forming the cuticle of the pileus. The cheilocystidia and spores
readily distinguish it from H. pascuense Pk. but the pigmentation of
the two is quite similar, as is evidenced by Peck's plate (1900). H.
aurantiellum has the small spores of H. pumilum Lange but has a
buff-colored veil along with other differences.
46. Hebeloma immutabile sp. nov.
Pileus 2-4 cm latus, convexus vel planus, glutinosus, ad marginem minute squamulosus vel appendiculatus, glabrescens, obscure
vinaceobrunneus; odor et gustus mitis. Lamellae confertae, latae, adnatae, subcinnamomeae. Stipes 4-7 cm longus, 2.5-4 mm crassus,
sericeofibrillosus, brunneolus sed deorsum non brunnescens). Velum
sparsim, evanescens. Sporae 8-10 x 5-5.5 fLm, in "KOH" fulvae,
valde dextrinoideae, verruculosae, inequilaterales. Cheilocystidia 26 -38 x 8-12 VLm, utriformia vel clavata. Cuticula pileorum ixotrichoderma est. Hypoderma + cellulosa.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
17538; legit prope Port Angeles, Washington, 4 Oct 1941.
Pileus 2-4 cm broad, convex becoming plane, margin at first
incurved, surface glabrous to the marginal area where at first floccules
from the veil occur, the margin at first slightly appendiculate, surface
slimy-viscid, color + "Army Brown" to "Pecan Brown" and drying a
dingy vinaceous-brown over the margin and the disc reddish brown.
Odor and taste mild.