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

44

The Veiled Species of Hebeloma

fertae, angustae, adnatae. Stipes 2-3 cm longus, 4-6 mm crassus, pallidus deinde brunnescens, fibrillosus. Velum fibrillosum, + evanescens,
pallidum. Sporae 8-10 x 5-5.5 Lmm, + phaseoliformes, non dextrinoideae, subleves. Cheilocystidia 33-46 x 9-12 tim, demum 50-67 x 7 -10 tim, fusoid-ventricosa, obtusa.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
88621; legit prope Lincoln Creek, Pitkin County, Colorado, 16 Jul
1978.
Pileus 1-3.6 cm broad, obtuse to convex, the margin incurved,
becoming plane or nearly so, or margin finally uplifted, + evenly
"Prout's Brown" to "Buckthorn Brown" (dark to medium yellowbrown), opaque at all times, slowly becoming pale "Sayal Brown" in
aging, canescent at first and avellaneous over marginal area. Context
thin watery brown, fragile, odor and taste mild, FeSO4 staining base of
stipe gray (very slowly); KOH on cuticle of pileus no reaction.
Lamellae narrow, close, adnate, pallid becoming a pale vinaceousbuff, near "Sayal Brown" in age, not beaded and not stained.
Stipe 2-3 cm long, 4-6 mm thick, equal, pallid from a thin coating of veil fibrils, becoming bister from the base up, solid, surface
fibrillose from the thin veil but no annular zone evident.
Spores 8-10 x 5-5.5 [im, elliptic to ovate in face view, beanshaped to very obscurely inequilateral in profile, pale snuff brown in
KOH and about the same in Melzer's, appearing smooth under a
high-dry objective.
Hymenium.-Basidia 4-spored, 6-7 (8) Rm broad. Pleurocystidia
none. Cheilocystidia fusoid-ventricose, at first 33-46 x 9-12 Im but
becoming 50-67 x by 7-10 txm by the elongation of the neck, apex
obtuse, not branched or forked, lacking secondary septa.
Lamellar and pilear tissues.-Lamellar trama typical for the genus but hymenium and subhymenium reddish to orange in Melzer's.
Cuticle of pileus a tangled ixotrichodermium collapsing to an ixolattice, hyphae 2-3.5 JIm diam and with refractive walls, in Melzer's
reagent copious dextrinoid debris forming; clamps present. Hypodermium of yellow-brown inflated cells (as seen in KOH mounts of fresh
material), tawny as revived in KOH. Tramal hyphae of pileus typical
of the genus (no red content in Melzer's).
Habit, habitat, and distribution.-On soil on an overflow area of
a stream, Lincoln Creek, Pitkin County, Colorado, spruce nearby, July
16, 1978 (type, MICH).
Observations.-This species illustrates one reason why mature
specimens should be used for study of the cheilocystidia. At a certain
stage in the development of the fruiting bodies the cystidia apparently
elongate rather rapidly. One would expect them to agglutinate in age.