Summary:
Strossmayeria atriseda produces a minute brown fruitbody growing singly to gregariously on old moist wood, identified by microscopic characters.

Microscopic:
spores (26)30-37 x (3.7)4.4-7.3 microns, subfusoid [somewhat spindle-shaped], slightly clavate, J+, colorless, (1)4-5(7)-septate, gel sheath smooth and 0.7(1.5) microns wide, generally biseriate but rarely triseriate; asci 8-spored, (122)131-150(154) x 13-19 microns, clavate with long stem tapering down to a fine base, "with brown dextrinoid cytoplasmic contents when young, arising from croziers"; paraphyses exceeding asci by 7.3 microns, long and filiform [thread-like], "simple or divided, septate", tip slightly swollen in clavate or irregular shape, 1.5 microns wide in the middle, (1.5)2.2 microns wide at the tip; ectal excipulum "of textura oblita with very glassy walls, 12-16 microns wide in median section, J+ with a strong blue reaction, cells rectangular and elongate", 8-14(18) x (1.5)2.2-2.9 microns, apical cells with rounded tips; medullary excipulum and subhymenium not evident; base of fruitbody "composed of brown irregular cells, from which also arise conidiophores of Pseudospiropes", conidiophore "brown, septate, with large scars and a zig-zag shape due to the scars left by the secession of the conidia during sympodial conidiogenesis", (7.3)9.5-15(18) microns, "young conidiophores without scars, straight and thin, 7.3 microns wide, base slightly swollen", conidiogenous cell "terminal, lighter than the rest of the conidiophore, thin-walled with a round apex less than 0.7 microns wide, 21 x 8.8-10 microns", conidia (28)33-42 x (10)11-13(18) microns, basal scar thickened at the edges, (3.7)4.4-5.9(6.6) microns, (3)7(8)-septate, frequently septa very light and difficult to see, "apical and/or basal cells sometimes darker"

Notes:
A specimen was examined from BC (Iturriaga).

Synonyms and Alternate Names:
Merulius aureus Fr.
Plicatura aurea (Fr.) Parmasto