Summary:
Features include 1) resupinate growth on conifer wood, oak, and heath, 2) a white to sometimes grayish or creamy fruitbody, ranging from thin, delicate, more or less interrupted and somewhat pruinose, to densely continuous, cracked, almost membranous, the surface usually smooth but occasionally sparsely and minutely odontioid, the fruitbody closely adherent to separable, the margin indistinct, 3) spores that are cylindric, curved (when narrow), smooth, and inamyloid, 4) cystidia that are long-conic and capitate, the base bifurcate, the cystidium narrowing uniformly towards the apical bulb, the capillary lumen enclosed by the thick walls expanding rapidly at the neck to form the thin-walled apical bulb, sometimes collared by crystals, sometimes haloed or capped by an amorphous or crystalline mass, the cystidial wall inamyloid to strongly amyloid, the middle layer of the wall dissolving in 10% KOH, 5) occasional different cystidia that are subconic and lack a bulb, the lumen not capillary except in roots or not even there, relatively broad in the stem, with the wall thinning gradually to an elongate, thin-walled apex, and 6) context composed of hyphae with clamp connections. The description derived from Weresub(4) is of var. subquercina, but Weresub considered it to be more or less typical Peniophora juniperina and placed the name in synonymy with Peniophora juniperina, despite its occurrence on oak instead of conifer or heath.

Microscopic:
SPORES (4)4.75-7.25(8.5) x (0.75)1.0-2(2.5) microns, narrowly cylindric, where very narrow almost allantoid, (where broader scarcely curved), smooth, inamyloid, thin-walled; BASIDIA 7-15(18) x 3.5-4.25(5) microns, cylindric to clavate, "basal walls sometimes pronounced, more or less soluble in KOH", CYSTIDIA 50-95 microns long, (3.5)5.5-7.5(9) microns wide near base, stem narrowing to a neck width of 3-5(5.5) microns, "where the capillary lumen expands more or less abruptly to form thin-walled apical bulbs" (5)7-10(11) x (6)7-9(11.5) microns, "apices sometimes heavily massed with crystals", stem walls smooth, dissolving in KOH, inamyloid to amyloid; SUBICULUM "composed mainly of indistinct hyphae", 2-2.75 microns wide, with clamp connections, sometimes with somewhat thickened walls that dissolve in KOH, (Weresub(3)), SPORES (few seen) 5.5 x 1.5 microns, cylindric, curved, (according to Donk 5-6 x 1.5-1.75-2 microns), smooth, inamyloid, thin-walled; BASIDIA (few measured) about 15 x 4.3 microns, flexuous cylindric to clavate to obovoid, usually narrowing sharply in lower part; CYSTIDIA "self-capitate", with subconic stem, 30-65 microns long (according to Donk up to 75 microns), (3)4.5-6.5 microns wide just above base, the base usually furcate, "sometimes distinctly truly bi-rooted", cystidia narrowing more or less uniformly to a neck width of (2)3-3.8(5) microns, "lumen capillary in base and stem, expanding abruptly at neck to form thin-walled apical bulbs" (4)9-11 x (4)8.5-10 microns, "sometimes collared by crystals, sometimes haloed or capped by an amorphous or crystalline mass", "wall varying in amyloidity from negative to strongly positive, smooth, thick, middle layer soluble in 10% KOH"; occasional cystidia subconic and lacking bulb, "lumen not capillary except in roots or not even there, relatively broad in stem, with wall thinning gradually to elongate, thin-walled apices"; context composed of HYPHAE up to 3 microns wide, firm-walled, septa with clamp connections, (Weresub(4))

Notes:
Tubulicrinis juniperinus has been found in BC, OR, ID, ON, PQ, and MA, (Ginns).

Synonyms and Alternate Names:
Tremella uliginosa P. Karst.