Xenonectriella lutescens  

Anamorph: not known.
Teleomorph: stromata absent. Ascomata perithecia, 150-200 µm diam. and 200-300 µm tall, intensively red throughout, becoming brown with age, ovoid to pyriform, with a truncate apex and sometimes with a small papilla, ostiolate, immersed in lichen thalli with only the ostiolar areas visible as red to brown spots, scattered or in clusters. Peridium 40-50 µm thick near the ostiole, 20-35 µm thick below, with an outer layer of thick-walled orange-red angular rounded to elongate cells 5-9 µm diam. and an inner layer of hyaline compressed cells; becoming intensively yellow with lactic acid, K+ strongly violet. Interascal tissue ± absent, with numerous straight, filiform apical paraphyses 1-2 µm diam.; occasional, sparsely branched thin-walled paraphyses 2-6 µm diam. and constricted at the septa also observed between the asci. Asci (70-) 72-92 (-100) x 8-10 (-11) µm, cylindrical, with a long stipe, thin-walled and not fissitunicate, the apex without evident apical structures, originally with 8 (0-) 1-septate ascospores, which later fuse to form  (1-) 2 (-4) clusters. Ascospores originally (7- ) 10-16 (-20) x (6-) 7-10 (-12) µm, ellipsoidal, later fused into irregular ± cylindrical clusters (19-) 22-38 (-65) x (7-) 9-11 (-13) µm, the size dependent on the number of included spores, with ± rounded ends, transversely pluriseptate (septa to at least 12, often oblique and sometimes forming a zigzag) to occasionally submuriform, often markedly constricted and sometimes slightly bent at the septa; becoming pale yellow-brown, the wall smooth (often appearing tuberculate due to numerous small lipid guttules) to somewhat wrinkled in old spores, without a gelatinous sheath.