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.
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)
Notes: 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).
Habitat and Range
SIMILAR SPECIES
Botryobasidium obtusisporum has larger spores and basal hyphae that are at most 10 microns wide (Breitenbach).
Habitat
mostly on hardwood, rarely on conifers, in humid fertile biotypes, (Eriksson), on dead wood of hardwoods, according to literature also rarely of conifers, (Breitenbach), on twig; bark; barkless branches and logs; ground; on a variety of hardwood and conifer species; associated with a white rot, (Ginns), fall, winter, spring; also on old polypore fruitbodies and bracken debris, (Buczacki)