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

Summary:
Features include 1) resupinate growth on wood (mostly hardwood), 2) fruitbodies that are pink, ranging from circular and small to large and conspicuous, mostly uneven with low tubercles and wrinkles, tightly attached when young, 3) spores that are elliptic, smooth, inamyloid, and colorless, the spore print light red, 4) a surface layer consisting of a) richly branching hyphidia, b) narrowly clavate basidia in various stages of development that penetrate the surface when mature, and c) thin-walled hyphae, and 5) a monomitic hyphal system, the hyphae with clamp connections, and the basal hyphae thick-walled.

Corticium roseum has been found in BC, WA, OR, ID, MB, NS, ON, NB, AL, AZ, CA, CO, DC, GA, IA, IL, IN, MA, MD, ME, MI, MN, MO, MT, NC, NJ, NM, NY, OH, PA, VT, and WI, (Ginns), Sweden and Finland, (Eriksson), and Switzerland and Asia, (Breitenbach).

Fruiting body:
resupinate, orbicular [circular in outline] when growing on smooth bark, effused on barkless wood, confluent and sometimes large and conspicuous, 0.01-0.05cm thick, consistency soft-membranaceous when young and live, tough when old; when growing well colored rose red, but fading with time and especially in herbarium to pale ochraceous red and finally ochraceous, "sometimes whitish because of an accumulation of encrusting crystals in the hymenial layer"; surface "mostly uneven with low tubercles and low ridges"; margin fimbriate [fringed] when young, not especially differentiated when old, (Eriksson), resupinate, initially as round spots that later grow together and may form expanses several decimeters across, 0.03-0.1cm thick, attached tightly to wood when young, sometimes detaching at margin when older, flesh "membranous-waxy to corky-toughish"; "surface undulating, tuberculate to radially wrinkled, dull, bright to pale pink (a scratch made with a finger nail on the hymenium turns darker red)"; margin "irregular and distinctly bounded to slightly fringed", (Breitenbach), spore deposit white (Buczacki)

Microscopic:
SPORES 9-16 x 6-10 microns, elliptic, smooth, inamyloid, thin-walled, spore print light red; subhymenium thickening, composed of thin-walled hyphae, basidia in various stages of development, and numerous dendrohyphidia; BASIDIA "starting as probasidial, ellipsoid or angular bladders in the autumn, in late spring developing a tubelike metabasidial part of varying length, depending on the position of the probasidium", but mostly the total basidium measuring 40-60(70) x 5-7 microns, basidia 4-spored, with clamp connection; DENDROHYPHIDIA numerous, forming a covering layer in sterile state (but penetrated by basidia when fertile), richly and irregularly branched, crystalline grainy encrustation especially in old specimens, mostly colorless but often yellowish under the microscope; CYSTIDIA none; HYPHAE monomitic richly branched and with clamp connections, those of the subiculum mostly horizontal with thickened walls, (Eriksson), SPORES 10.5-12 x 6.5-8 microns, oval to broadly elliptic, smooth, inamyloid, colorless; BASIDIA 4-spored, 80-90 x 9-10 microns, narrowly clavate, often strongly sinuous; DENDROHYPHIDIA 1-2 microns wide, strongly branched, imbedded in hymenium, with crystals in older specimens; CYSTIDIA not seen; HYPHAE monomitic 2-4 microns wide, with clamp connections, BASAL HYPHAE thick-walled, (Breitenbach)