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

The Subgenus Hebeloma

101

Pileus 3-7.5 cm broad, obtuse to convex, margin inrolled and
faintly pruinose to cottony-fibrillose, expanding to broadly convex in
age, surface glabrous, viscid, "Verona Brown" to "Cinnamon," in
some the disc a darker reddish brown, not truly hygrophanous but
gradually becoming pinkish buff, sometimes radially rugulose. Veil
rudimentary, evident on buttons in which the cap margin was + 1 mm
from the stipe. Context whitish to pallid, thin, taste bitterish, odor
faint and not distinctive.
Lamellae broad, close to subdistant, adnate, becoming adnexed,
pallid brownish when young, dark vinaceous-brown ("Rood's Brown"
to "Walnut Brown") when mature.
Stipe 3-6 cm long, 4-9 mm thick, equal, solid or with a narrow
pith, whitish above, brownish below, becoming bister (spadiceous)
from the base upward, apex innately squamulose at first, more fibrillose to fibrillose-squamulose downward, veil rudimentary, pallid.
Spores 7-9 x 4.5-5 Jim, in profile view + inequilateral, in face
view ovate, pale clay color in KOH, dextrinoid, minutely roughened.
Hymenium.-Basidia 4-spored, 22-27 x 5-6 pIm, projecting
when sporulating. Pleurocystidia none. Cheilocystidia small, 18-30 x
3.5-6 (Im, filamentous to ventricose at base and with a flexuous neck,
apex obtuse, hyaline to yellowish in KOH, agglutinating.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus a narrow ixocutis of hyphae 2-4 xm diam, hyaline, walls refractive, clamps present, hyphae much branched. Hypodermium intermediate as to type, yellow in KOH.
Habit, habitat, and distribution.-Gregarious on cow dung in a
pasture, Crescent City, California, December 3, 1937 (type, MICH).
Observations.-This is a very distinct species by virtue of its habitat alone, but if habitat is disregarded, the bitter taste, dark vinaceousbrown gills and the small dextrinoid spores amply distinguish it.
49. Hebeloma olympianum sp. nov.
Pileus 1-2.5 cm latus, obtusus deinde campanulatus vel planoumbonatus, tenuiter fibrillosus, glabrescens, viscidus, cinnamomeus;
odor et gustus mitis. Lamellae pallidae demum brunneolae deinde cinnamomeae, confertae, latae, adnatae. Stipes 2-4 cm longus, 2.5-3.5
mm crassus, tenuiter fibrillosus, glabrescens, deorsum brunnescens.
Sporae 7-9 x 4-5.5 im, minute verruculosae, leviter dextrinoideae,
inequilaterales. Cheilocystidia (18) 22-27 x 4-7,m, + filamentosa
vel anguste clavata. Cuticula pileorum ixotrichoderma est.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
17972; legit prope Storm King Mt., Olympic National Park, Washington, 16 Oct 1941.