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

The Subgenus Hebeloma

87

from the remains of a white fibrillose veil, as dried + concolorous with
pileus.
Spores 9-13 x 6.5-8 Im, surface faintly marbled, pale clay color
in KOH, + dextrinoid; shape in profile inequilateral, in face view
ovate to broadly ovate with the apex blunt.
Hymenium.-Basidia 4-spored, 7-9 (10) Jim broad, projecting
when sporulating. Pleurocystidia none. Cheilocystidia scattered 36-58
x 7-10 x 6-7 x 7-9 Jim, cylindric-subcapitate, fusoid-ventricose with
a + enlarged apex or + elongate-clavate and elongating considerably,
surface + viscid (as judged by adhering spores).
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus an ixocutis to an ixolattice, the hyphae 1.5-3 im
diam, hyaline refractive in KOH, clamps present. Hypodermium hyaline revived in KOH, yellowish to reddish tawny in Melzer's, + cellular, the cells 20-40 Jm diam, some hyphal fragments also present,
hyphal walls smooth and thin. Tramal hyphae ~ typical for the genus
(radial-interwoven and the hyphal cells + inflated), merely yellowish
in Melzer's.
Habit, habitat, and distribution.-Gregarious in brushy areas
along an old ditch, French Creek Grade, Salmon River, Idaho, near
the town of Burgdorf, September 4, 1964 (type, MICH).
Observations.-The raphanoid odor and taste and a slowly discoloring stipe are distinguishing field features. The odor and taste of H.
barrowsii distinguishes that species from H. salmonense as do the more
highly ornamented spores.
39. Hebeloma barrowsii sp. nov.
Pileus 2-4.5 cm latus, demum late convexus, glaber, viscidus,
albus vel subalbidus; contextus subalbidus; sapor amarellus ("unpleasant"-Barrows); (odor "woody"-Barrows). Lamellae albae demum
argillaceae, confertae, angustae. Stipes 3-5 cm longus, 4-6 mm crassus, albus, deorsum demum leviter umbrinus. Velum fibrillosum.
Sporae 10-12.5 x 5-7 jLm, sublimoniformes, tarde et leviter dextrinoideae. Basidia tetraspora. Cheilocystidia (34) 46-68 x 4-6 x 8-14 Jim,
elongato-clavata vel filamentosa vel capitata.
Specimen typicum in Herb. Univ. Mich. conservatum est, Barrows 3056; legit prope Hyde Park, elev. 8,000 ft, Santa Fe, New Mexico, Sep 1965.
Pileus 2-4.5 cm broad, + convex becoming broadly convex, the
margin at first incurved, glabrous, viscid, white, becoming dingy but as
dried whitish ("Pale Pinkish Buff"). Context whitish, taste unpleasant,
odor "woody" (Barrows).