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

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The Veiled Species of Hebeloma

28. Hebeloma sanjuanense sp. nov.
Pileus 2-4 cm latus, convexus, demum planus vel expandoumbonatus, ad centrum glaber, ad marginem argillaceo-fibrillosus, ad
centrum + rubrobrunneus, odor et gustus raphaninus. Lamellae adnatae, confertae, latae, obscure cinnamomae. Stipes 4-6 cm longus, 3-5
mm crassus, brunnescens. Velum sparsim, pallide argillaceum. Sporae
8.5-10 x 5-5.5 tum, subleves, phaseoliformes, ovoideae, vel ellipsoideae, non dextrinoideae. Cheilocystidia 30-45 x 5-7 pxm, filamentosa,
flexuosa, inconspicua.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
51736; legit prope Lizard Head Butte, San Juan County, Colorado, 3
Aug 1956.
Pileus 2-4 cm broad, obtuse to convex becoming ~ plane or with
a slight umbo, glabrous over disc, with cinnamon-buff veil remnants
along the margin at first, color over disc a dull vinaceous-brown ("Verona Brown"); context thin, odor and taste raphanoid.
Lamellae adnate, close, broad, at first with a vinaceous tint (in
artificial light), soon + "Sayal Brown," edges even, not beaded.
Stipe 4-6 cm long, 3-5 mm thick, equal, fragile, soon darkening
from base upward; veil remnants soon vanishing.
Spores 8.5-10 x 5-5.5 Vim, pale yellow in KOH and appearing
smooth, ovate to elliptic in face view, ~ bean-shaped in profile to
subelliptic, rarely obscurely inequilateral, not dextrinoid.
Hymenium.-Basidia 4-spored, 24-29 x 6-8 pIm. Pleurocystidia
none. Cheilocystidia 30-45 x 5-7 [xm, filamentous, flexuous, hyaline,
inconspicuous.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus an ixolattice, elements 2-4 Vxm diam, often
branched, some encrusted with hyaline to brown pigment. Hypodermium cellular, cell walls heavily encrusted and pigmented. Clamp connections present.
Habit, habitat, and distribution.-Scattered under conifers, Lizard
Head Butte, near Teluride, San Juan County, Colorado, August 3,
1956 (type, MICH).
Observations.-This species differs from H. mesophaeum in the
shape and size of the cheilocystidia, in the thicker more gelatinous
cuticle of the pileus and in the color of the veil. H. pumilum Lange has
small cheilocystidia but has a bitter rather than raphanoid taste and
was collected under Fagus. Also, Lange's illustration of H. pumilum
(1938-40, pl. 119B) indicates a white veil and spores inequilateral in
profile view.