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

Summary:
Also included in Corals category. Cotylidia diaphana has 1) a whitish to pale brown, translucent fruitbody which is vase-shaped or funnel-shaped or split into petal-like lobes, with radiating silky fibrils on the upper surface, 2) the undersurface smooth but under a hand-lens bristly, 3) slender smooth stem, 4) growth on the ground, 5) whitish spore deposit, and 6) cystidia on the lower (spore-bearing) surface. Molecular work places Cotylidia in the Rickenella clade that falls either in Hymenochaetales or Agaricales.

The distribution includes WA, PQ, AL, CA, IA, IL, IN, MI, MN, MO, NY, OH, PA, UT, and WV, (Ginns), and MS (Lincoff). It is also reported from Argentina, Brazil, Jamaica, and China, (Reid). There is one collection from BC with this label at the Pacific Forestry Centre determined by J. Hanson.

Cap:
0.5-3cm wide, "vase-shaped or funnel-shaped or often split into petal-like lobes"; "whitish to buff or pale hazel-brown, sometimes with obscure concentric zones"; upper (inner) surface dry, with fine radiating silky fibrils, (Arora), 0.5-3cm wide, 1.5-4.5cm high, "deeply vase-shaped or split into spatula-like sections, with even or torn margin", translucent; white to pinkish buff or somewhat darker; "resinous, somewhat radially lined and zoned", (Lincoff), 0.8-3cm wide, 1.5-4cm high, normally discrete, frequently infundibuliform [funnel-shaped] but sometimes pseudoinfundibuliform or even spathulate, occasionally becoming deeply split into a number of lobes, and each of these may develop into individual caps that often fuse to form complicated fruitings (the same effect may result from the fusion of adjacent fruitbodies); cap white or pallid when fresh, becoming creamy-buff, pale ochraceous or straw colored with a slight sheen in the herbarium (dried material may develop darker zones or banding and this color may sometimes predominate); upper surface of distinct, radiating, rope-like fibrils, sometimes rather coarse, "especially at the base of the fruitbody where they may form spiculose processes", (Reid)

Flesh:
thin, tough, (Arora), leathery (Lincoff), fruitbody thin coriaceous [leathery] (Reid)

Underside:
spore-bearing lower (outer) surface smooth or somewhat uneven, whitish to buff, pinkish buff, or tinged cap color, (Arora), lower (outer) surface white to pinkish buff; "appearing smooth, but minutely ridged and bristly under hand lens because of protruding cystidia", (Lincoff), hymenial surface white or light cream when fresh (reddish brown or ochraceous with salmon pink tints when dried), smooth or radiately wrinkled, often somewhat decurrent down the stem, (Reid)

Stem:
0.5-3.5cm x 0.1-0.2cm, more or less central, solid; colored as the rest of the fruitbody; smooth; "base usually with white mycelial down", (Arora), 0.5-3.5cm wide, slender with matted white down, small ball of mycelium at base, (Lincoff), 0.5-2.5cm x 0.15-0.4cm, white, "minutely floccose or tomentose especially at the base", (Reid)

Microscopic:
spores 4-6(8) x 2.5-4 microns, elliptic, smooth; long narrow projecting cystidia present, (Arora), spores 4-6 x 2.5-4 microns, elliptic to oval, smooth, colorless; cystidia 69-100 x 9.5-13 microns, colorless, hair-like, thicker than basidia and projecting beyond them, (Lincoff), spores 4-6(7) x (2)2.75-3.5 microns, elliptic, thin-walled, colorless, with a distinct, oblique apiculus; basidia 4-spored, up to 28.6 microns long and 5-6 microns wide, clavate or subcylindric; cystidia up to 130 microns long and 8-15 microns wide, long cylindric or slightly clavate, thin-walled, originating in the trama just above the hymenium, may project up to 80 microns beyond the basidia, may become 1-septate; hymenium thickening, reaching 78 microns thick at a point 0.5cm from the margin of the fruitbody; hyphal structure monomitic, consisting of generative hyphae 2-6(7) microns wide, colorless, branched, walls thin or distinctly thickened, clamp connections absent, (Reid(6))

Spore Deposit:
whitish (Arora)