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

Summary:
Features include 1) resupinate growth on wood, 2) a soft, fibrous, cottony, often bumpy fruitbody that is granular and honey-yellow to brownish in the center and toward the margin increasingly filamentous and bright yellow, ending in whitish rhizomorphs, 3) a fruitbody that turns wine-red in KOH, 4) spores that are nearly round to elliptic, with dense short spines, inamyloid, and colorless, 5) pleural basidia, and 6) a monomitic hyphal system, the hyphae with clamp connections, the subhymenial hyphae richly branched and sinuous, the subicular hyphae straight and often encrusted with crystals.

Xenasmatella vaga has been found in BC, WA, ID, AB, MB, NB, NS, ON, PQ, AK, AL, AZ, CA, CO, IL, IN, MA, MD, MI, MN, MO, MT, NC, NH, NJ, NM, NY, OH, PA, TN, UT, VT, and WI, (Ginns). It is the most common species of the genus and widespread in Scandinavia (Hjortstam). Distribution also includes Switzerland and Asia (Breitenbach).

Fruiting body:
resupinate, appressed tightly to substrate, forming filamentous to membranous patches 0.02-0.05cm thick and several centimeters to decimeters across, "consistency fibrous, cottony, soft"; "in the center granular, dull, honey-yellow to brownish, increasingly filamentous toward the margin, cottony, bright sulphur-yellow, and ending in fine, whitish, fanlike rhizomorphs, older fruitbodies often overgrown with branched, yellow rhizomorphs"; fruitbody turning wine-red in KOH, (Breitenbach), resupinate, effused [spread out], easily detachable, "often large, smooth, colliculose to grandinioid or comprised of richly branched and anastomosing hyphal threads, often arranged in a fan-like manner", fragile to membranaceous; varying in color "but always with some shade of brown from chamois to deep umber", when fresh "usually with more yellowish colors, especially in sterile parts which can be sulphur-yellow"; margin abrupt or thinning out and then arachnoid [cobwebby] or fibrillose, usually of paler color; rhizomorphs "frequently occurring in the fruitbody and extending beyond the margin", (Hjortstam(6)), spore deposit white (Buczacki)

Microscopic:
SPORES 4-5.5 x 3.5 microns (excluding spines), elliptic, short-spined, inamyloid, colorless; BASIDIA 4-spored, 13-22 x 5-6.5 microns, clavate, with basal clamp connection; CYSTIDIA not seen; HYPHAE monomitic, 3-5 microns wide, yellowish, in part encrusted, with clamp connections, (Breitenbach), SPORES (4.5)5-5.5(7) x 4-4.5 microns, subglobose to elliptic, densely verruculose, inamyloid; BASIDIA subspherical to subclavate, sinuous, pleural, mainly 15-20 x 5-6 microns, 4-spored, with basal clamp connection; HYPHAE monomitic, with clamp connections, thin-walled; subicular hyphae and rhizomorph hyphae 2-5 microns wide, straight, "often provided with crystals and now and then with slightly ampulliform septa, slightly agglutinated", subhymenial hyphae 2-3 microns wide, sinuous, richly branched, hyphae turning vinaceous red in KOH, (Hjortstam)