E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Fieldmarks include a brown, moist, often appendiculate cap, whitish to grayish then dingy lilaceous gray brown gills, a long, pallid to brownish, dry stem, a mild taste, clustered fruiting on rotting conifers, and dark spores. Hypholoma capnoides is common in the Pacific Northwest.

Smith(25) examined collections from BC, WA, OR, ID, ON, QC, CA, MI, NY, and TN. Breitenbach gives the distribution as North America, Europe, and Asia.

Cap:
2-7cm across, convex or slightly umbonate to flat; "yellow to tawny, orange-brown, rusty-brown, or cinnamon, the margin often yellower"; smooth, not viscid, margin often hung with veil remnants, (Arora), 2-4(6)cm across, obtusely conic-convex becoming convex to flat, margin incurved for a long time; "olive-yellow to maize-yellow when moist, orange-yellow in the center, pale yellow to honey yellow when dry, center remaining orange-yellow", margin pale to whitish; smooth, dull, margin "hung with fine, white, fibrillose veil remnants when young", (Breitenbach), moist but not viscid (Ammirati), "Unusual for a hypholoma, it can have a viscid cap, although most guides report it as dry to moist only", (Trudell)

Flesh:
thin; pallid, (Arora), +/- thin; olive-yellow when moist, whitish when dry, (Breitenbach), quite firm; whitish, (Ammirati)

Gills:
usually adnate but often seceding, close, narrow; "at first pallid, then grayish, finally dark gray brown to purple-brown", (Arora), broadly adnate, 34-40 reaching stem, 7 subgills between neighboring pairs of gills, broad; "cream-colored when young, then gray-white with a lilac tint, olive-blackish in age", edges whitish; edge smooth, (Breitenbach)

Stem:
5-10cm x 0.3-0.8(1)cm, equal or tapered downward, often long in relation to cap; pallid or yellowish in upper part, often rusty brown to tan or brownish in lower part; dry, (Arora), 2-7cm x 0.2-0.7cm, cylindric, often curved, elastic, hollow, base usually joined with several others; "upper half light yellow with the apex whitish, lower half red-brown"; finely longitudinally fibrillose, (Breitenbach), showing a few traces of veil (Ammirati)

Veil:
evanescent [fleeting] "or leaving small patches of tissue on cap margin" and sometimes an obscure fibrillose zone on stem, (Arora)

Odor:
pleasant (Phillips), pleasantly fungoid (Breitenbach), none (Miller)

Taste:
mild, (Arora, Phillips), mild or only slightly bitter (Rinaldi), mild, fungoid, (Breitenbach)

Microscopic spores:
spores 6-7.5 x 3.5-4.5 microns, elliptic, smooth, germ pore present, (Arora); spores 6.9-8.7 x 3.9-5.2 microns, elliptic, smooth, thick-walled, with a germ pore, spores gray-yellow, with a reddish border; basidia 4-spored, 22-28 x 6-7 microns, cylindric, with basal clamp connection; pleurocystidia modified as chrysocystidia, 28-36 x 8-16 microns, cheilocystidia "fusiform to lageniform, in part thick-walled, a few chrysocystidia present, with an apical protrusion, 20-45 x 6-15 microns"; clamp connections mentioned for cap cuticle and basidia, (Breitenbach), spores 6-7 x 4-4.5 microns, elliptic in face and side view, hardly flattened on one side in side view, smooth, germ pore small but distinct, dull yellowish brown or honey-color in water or alkali; basidia 4-spored, 17.5-20 x 5-6 microns, clavate; chrysocystidia present on gill faces, 20-30 x 7.5-10 microns, obovate-mucronate to clavate, with highly refractive amorphous body that yellows in alkali, cheilocystidia 15-25 x 6-10 microns, fusiform to ventricose with obtuse apices, or obovate-mucronate, colorless, rarely with yellowing contents; cap cuticle of narrow filamentous hyphae 3-5 microns wide "overlaying swollen, ellipsoid, rusty tawny, encrusted hyphae" 10-15 microns wide; clamp connections present, (Watling)

Spore deposit:
purple-brown to deep purple gray (Arora), violet-brown (Breitenbach)