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

The Subgenus Hebeloma

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meae. Stipes 3-6 cm longus, 4-8 (11) mm crassus, aequalis, albidus
tarde brunnescens. Velum bicoloratum (ochraceum et albidum).
Sporae 7-9 x 5-5.5 Rm, ovoideae vel ellipsoideae, non dextrinoideae. Cheilocystidia 28-43 x 5-7 Ipm, fusoid-ventricosa vel clavata
vel subcylindrica.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
58632; legit sub Pinus albicaulis, prope Riggins, Idaho, 5 Jul 1958.
Pileus 2-4 cm broad, convex with an incurved margin, becoming
broadly convex to plane, the margin spreading and + wavy in age at
times, + evenly cinnamon in color, marginal area at first decorated
with patches of veil fibrils but soon glabrous, viscid to thinly slimy in
wet weather, opaque. Context pallid to brownish, odor and taste
raphanoid.
Lamellae broad at maturity, moderately close to subdistant, adnate, seceding, at first pinkish buff but becoming pale rusty cinnamon,
edges even, not beaded.
Stipe 3-6 cm long, 4-8 (11) mm thick, equal, white at first and
decorated with veil remnants (the outer layer cinnamon-buff, the inner
layer white to pallid); becoming clay color or darker from the base
upward.
Spores 7-9 x 5-5.5 Im, ovoid to ellipsoid or in profile view
some obscurely inequilateral, appearing smooth, nearly hyaline in
KOH, weakly yellowish in Melzer's (not dextrinoid).
Hymenium.-Basidia 4-spored, 6-7.5 Im broad near apex. Pleurocystidia none. Cheilocystidia 28-43 x 5-7 x 7-9 rxm, versiform:
subcylindric, + clavate, or obscurely fusoid-ventricose, hyaline as
mounted in KOH, thin-walled, scattered.
Lamellar and pilear tissues.-Lamellar trama pale rusty cinnamon
in sections mounted in KOH, otherwise typical for the genus (no red
color in mounts in Melzer's). Cuticle of pileus an ixolattice (possibly an
ixotrichoderm when very young), the elements 1.5-2.5 Rxm diam, refractive in KOH, clamped. Hypodermium cellular to hyphoid (intermediate as to type), pale fulvous in KOH, redder in Melzer's, incrustations scattered on the hyphal walls. Tramal hyphae + ochraceous in
KOH.
Habit, habitat, and distribution.-Gregarious under Pinus albicaulis, Heaven's Gate Ridge, Seven Devils Mts. near Riggins, Idaho,
July 5, 1958 (type, MICH).
Observations.-The moderately copious bicolored veil and the
radishlike odor and taste separate this species from H. versipelle where
we first tried to place it. Its tree associate was clearly with the local
alpine 5-needle pine. The cheilocystidia separate it from H. bicoloratum var. coloradense, a variety associated with spruce.