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

148

The Veiled Species of Hebeloma

pallide rufobrunneae, confertae, demum latae et ventricosae. Stipes 2 -4 cm longus, 2-2.5 mm crassus, pallidus. Velum pallidum, fibrillosum.
Sporae 10-14 (15) x 6.5-8 JIm, limoniformes, rugulosae, non dextrinoideae. Cheilocystidia 32-46 x 7-10 Im, fusoide ventricosa.
Specimen typicum in Herb. Univ. Mich. conservatum est, Smith
46221; legit prope Redfish Lake, Stanley, Idaho, 17 Aug 1954, Bigelow and Smith.
Pileus 1.5-3 cm broad, obtuse to convex, the margin incurved,
expanding to broadly convex to plane, margin pallid from a thin coating of veil fibrils, ground color about "Warm Sepia" or a darker redbrown, drying to a pale to medium "Army Brown" or "Verona
Brown." Context thin, brownish, odor and taste strongly raphanoid.
Lamellae broad and ventricose, close, adnate, white at first,
slowly becoming "Verona Brown" and where colored by spores
slightly more rusty cinnamon, not beaded or spotted.
Stipe 2-4 cm long, 2-2.5 mm thick, equal, pallid and thinly fibrillose, gradually becoming dark brown from the base upward, apical
area silky; veil scanty, white to pallid.
Spores 10-14 (15) x 6.5-8 Vlm, distinctly roughened under highdry objective, rarely slightly calyptrate, pallid singly, dull brownish,
about clay color in groups (mounted in KOH), in profile view broadly
inequilateral, in face view ovate, not dextrinoid (or at most weakly so
in ~ 30 minutes).
Hymenium.-Basidia 4-spored, 8-11 Vlm broad near apex. Pleurocystidia none. Cheilocystidia scattered along the gill edge, subcylindric to fusoid ventricose, 32-46 x 7-10 ILm, collapsing in age and
often difficult to demonstrate, apex obtuse.
Lamellar and pilear tissues.-Lamellar trama typical for the genus. Cuticle of pileus a thin ixocutis or a "subixocutis"; the hyphae 2-5
Jim diam, + tubular, hyaline, walls somewhat refractive. Hypodermium cellular, of rusty brown elements heavily encrusted, redder
brown in Melzer's, no dextrinoid debris observed. Tramal hyphae typical of the genus but in general a red flush present throughout mounts
made in Melzer's. Clamp connections present.
Habit, habitat, and distribution.-On duff under pine, Redfish
Lake, Stanley, Idaho, August 17, 1954, Bigelow and Smith (type,
MICH).
Observations.-The spores readily distinguish this species from
H. mesophaeum sensu lato, but the pileus does resemble it in color.
The critical features for identification are: (1) the large ornamented
spores inequilateral in profile view, (2) the very rudimentary ixocutis
over the pileus, (3) the heavy incrustations on the walls of the hypodermial elements, (4) the slowly and weakly dextrinoid spores, (5) the