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

Summary:
Features include 1) resupinate growth on wood, 2) a loosely interwoven fruitbody with a netted to web-like surface, whitish in color, 3) spores that are obliquely oval, smooth, inamyloid, and colorless, the walls somewhat thickened, with a distinct apiculus, 4) a monomitic hyphal system, the basal hyphae wide, rather thick-walled, light brownish, and without clamp connections, 5) hyphae roughened by fine projections. Note however that Botryobasidium laeve (Eriksson) Parmasto, which has smooth hyphae, is synonymized by Ginns (fide Maekawa) with this species, and Breitenbach(2) say the smooth hyphae are the only difference.

Botryobasidium pruinatum has been found in BC, WA, OR, MB, NS, ON, PQ, AK, AL, AZ, CA, CO, IA, MA, MD, MN, MO, NC, NM, NY, OH, PA, RI, and VA, (Ginns). It occurs in Europe including Scandinavia (Eriksson) and Switzerland (Breitenbach).

Fruiting body:
loosely interwoven, resupinate, at first reticulate [netted] hypochnoid [with dry rather loosely intertwined hyphae arranged flat on substrate], then more confluent; grayish white or when old yellowish or pale ochraceous, (Eriksson), resupinate, loosely attached, consistency cottony and soft, "forming thin, open-tomentose patches several centimeters to decimeters in extent"; white to cream; smooth; margin thin, (Breitenbach), spore deposit white, (Buczacki)

Microscopic:
SPORES 5-8 x 2.5-3.5 microns, obliquely oval, smooth, walls somewhat thickened, with very distinct apiculus; BASIDIA 17-25 x 7-10 microns, at first rounded, then obovate to subcylindric, more or less constricted; HYPHAE monomitic: hyphae without clamp connections, most more or less asperulate [roughened by fine projections], BASAL HYPHAE 15-20 microns wide or more, yellowish to brownish yellow, thick-walled, with sparse branching, hymenial hyphae narrower, basidial branches 4.5-6 microns wide, thin-walled, colorless, (Eriksson), SPORES 5.5-8 x 2.5-3.5 microns, oval elliptic, smooth, inamyloid, colorless, cyanophilic, rather thick-walled, with distinct apiculus, with droplets; BASIDIA 6-spored, 18-22 x 6-8 microns, cylindric, somewhat constricted, without basal clamp connection; CYSTIDIA not seen; HYPHAE monomitic: all hyphae finely verrucose, hyphae 6-8 microns wide, thin-walled, BASAL HYPHAE up to 17 microns wide, rather thick-walled, light brownish, septa without clamp connections, (Breitenbach)