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

Summary:
Features include 1) resupinate growth on conifers, 2) pinkish or reddish color with a conspicuous white margin, 3) spores that are allantoid, smooth, and colorless, 4) a pale red spore print, 5) cystidia of 2 types: a) thick-walled encrusted metuloids, and b) elongated thin-walled sulfo-positive gloeocystidia, and 6) a monomitic hyphal system, the hyphae with clamp connections.

Peniophora septentrionalis has been found in BC, AB, NF, NS, NT, ON, PQ, SK, and CO, (Ginns), as well as Finland, Sweden, and the USSR, (Eriksson).

Fruiting body:
0.01-0.04cm thick, resupinate, adnate [firmly attached] but loosening from the margin, orbicular [circular], then confluent and irregularly effused; when young rose-red to light grayish red, fading in herbarium, when older gray-violaceous and finally gray-brown; "at first smooth, then more or less tuberculate or with irregular ridges"; sterile margin of growing specimens 0.1-0.2cm wide, white, finely fimbriate [fringed], "disappearing in older, rolled back specimens", (Eriksson), at first small, orbicular [circular], and remaining so or coalescing and spreading over large areas, at first adherent, later often loosening at margin; when fresh pinkish or reddish, fading on drying to pinkish gray or violaceous, or brownish gray; "smooth or with slightly raised ridges or knobs"; "the margin usually white and conspicuous", (Nobles)

Microscopic:
SPORES 6.5-8 x 2-2.5 microns, allantoid, smooth, colorless, thin-walled, spore print pale red; BASIDIA 4-spored, 40-50 x 5-6 microns, subcylindric or subclavate, with basal clamp connection; CYSTIDIA of 2 types: 1) thin-walled, acute hymenial cystidia that become encrusted and develop into strongly encrusted metuloids with the encrusted part 20-30 x 7-12 microns, 2) thin-walled sulfocystidia, 60-120 x 7-10 microns, "varying in number but always present"; HYPHAE monomitic, with clamp connections, young growing hyphae thin-walled and colorless, "older ones with thickened walls, more or less pigmented brown"; thickening subhymenium "composed of densely united, vertically arranged hyphae and cystidia, in older fruitbodies stratified"; subicular layer "well developed, composed of mainly horizontal hyphae, next to the substrate and to the subhymenium with dark brown pigmentation, less in the middle part of the subiculum" which in young fruitbodies is almost colorless, (Eriksson), SPORES 7.0-10.5 x 2.5-2.8(3.5) microns, cylindric, slightly curved, smooth, colorless, minutely apiculate; BASIDIA 4-spored, 4.9-6.3 microns wide, long, slender, flexuous [wavy], with clamp connection; CYSTIDIA of 2 types: 1) numerous throughout vertical layer, (23.0)35.0-70.0 x 7.7-15.6 microns, "at first thin-walled, pointed, with contents uniformly stained, the walls increasing in thickness until lumen is almost obliterated, colorless except for those cystidia or bases of cystidia in the brown layer", 2) gloeocystidia "fairly numerous in hymenium, frequently extending through whole vertical layer", 49.0-84.0 x 6.3-7.7 microns, long and flexuous [wavy] with obtuse apex, "thin-walled, the contents deeply stained, with oily inclusions"; IN SECTION, 268-320 microns, consisting of broad basal layer, 160-260 microns, in which hyphae are horizontally arranged, brown in a zone up to 20 microns wide next to the substrate, colorless elsewhere, "and a layer 47-100 microns wide in which hyphae are vertically arranged, brown in transition zone up to 20 microns wide, becoming paler toward the hymenium"; HYPHAE nodose-septate, those in the horizontal layer 2.8-4.2 microns wide, "densely interwoven but the individual hyphae remaining distinct", at first thin-walled, with contents stained in phloxine, "the majority soon empty, with walls more or less thickened, so that in section the horizontal layer is mainly unstained, occasionally traversed by a thin-walled hypha with stained contents", in brown zone next to substrate and in transition zone between horizontal and vertical layers "hyphae thick-walled, brown, cemented to form a compact, parenchyma-like layer with a continuous zone of parallel, brown hyphal tips at base of basidia", (Nobles)