Actidium hysterioides  

Ascomata hysterothecial with an inconspicuous longitudinal slit, black, smooth, sometimes concentrically striate, superficial, solitary or in small groups, when grouped often arranged radially, 0.25-0.3 mm long, ca 0.1 mm wide, ca 0.1 mm high, ellipsoidal to narrowly ellipsoidal from above, with a broad base and longitudinally semi-oblong with rounded ends when viewed from the side and then semi-globose in vertical transverse section. Peridium thin, brittle, with side walls predominantly prismatic-parallel, basally composed of fused interwoven red-brown hyphae (textura epidermoidea) and at the slit margin perpendicular and markedly elongate-parallel, with a layer of interwoven hyaline thin-walled hyphae forming the floor of the cavity. Interascal tissue composed of paraphysoids ca 1 µm diam, filiform with rounded ends, hyaline, smooth, sparsely septate, branched and anastomosed, exceeding the asci. Asci arising from croziers and in parallel from the cavity floor, 50-60 x 6 µm, cylindrical tapering to a lobed base, fissitunicate, apex rounded, J-, 8-spored. Ascospores 13-17 x 2-3 µm, narrowly ellipsoidal to fusiform, brownish, smooth, 1-septate, not or slightly constricted at the septum.