Helminthosphaeria triseptata  

Anamorph: not definitely known. Occasional dark brown clavate structures, similar to the poroid conidiogenous cells of other species of Helminthosphaeria, can be seen attached to the base of ascomata and/or attached to subicular cells.
Teleomorph: stromata absent. Ascomata perithecia, 350-450 µm diam. and 400-600 µm tall, superficial, scattered singly or in small clusters on the substratum,  pyriform with a strongly papillate ostiole, mid brown, covered with a mixture of thick-walled setose and hyphal hairs 4-6 µm diam., almost hyaline to mid brown and with a narrow lumina. Peridium composed of an outer layer of dark brown large globose cells, and an inner layer of flattened hyaline angular cells. Interascal tissue composed of copious hyaline very thin-walled paraphyses 2-3 µm diam., with thin-walled periphyses 3-4 µm diam. which develop from very thin-walled ± globose cells lining the neck. Asci 120-145 x 6-7 µm, narrowly cylindrical, thin-walled, not fissitunicate, with a long tapering stalk, the apex obtuse to rounded with a minute refractive apical ring ca 2.5 µm diam. and 0.5 µm thick, 8-spored. Ascospores 14-15.5 x 4.5-5.5 (-6) µm, ellipsoidal, fairly thin-walled, initially hyaline and aseptate but mostly becoming 3-septate and mid brown with age, a proportion with only one septum that can occur at the median or lower position, the septa distinctly thicker than the outer ascospore wall, without a gelatinous sheath or appendages.