Pyrenomycetes Species Page

Chaetosphaeria cylindrospora

Small separate ascomata
Small clustered ascomata
F.A. Fernández, Huhndorf, Joanne E. Taylor & K.D. Hyde, in Huhndorf, Fernández, Taylor & Hyde, Mycologia 93: 1073. (2001)

Figure from SMH3237, SMH3568
Complete Description
Ascomata broadly ovoid, rarely subglobose, dark brown, 185-320 µm diam, 255-338 µm high, superficial, occurring scattered to gregarious, base well-developed and strongly attached on the substratum,with few, scattered setae. Setae are brown, flexous, tapering to a rounded, apex that is lighter in color. Ascomal wall opaque in surface view in water and in lactophenol; in longitudinal section 41 µm thick at the base, narrowing to 26-31 µm laterally and toward the apex, composed of melanized, pseudoparenchymatic cells. Ascomal apex papillate, sometimes glossy, black. Paraphyses simple, septate, 5-8 µm wide, tapering toward the apex. Asci clavate, long-stalked, 75-147 x 9-20 µm, pedicels 38-53 µm long, 3-3.5 µm wide, unitunicate, thin-walled, without an apical ring, with eight, tetra-triseriately arranged ascospores. Ascospores broadly fusiform to cylindrical, with rounded ends, straight to slightly curved, hyaline, 6-7-septate, 25-32 x 4.0-5.0 µm, at times with a thin coating. Anamorph. Dematiaceous phialidic anamorph associated on the substrate (only on type collection). Colony appears as inconspicuous superficial rings of scant dark brown hyphae, sometimes surrounding small groups of ascomata on the type material. Conidiophores micronematous, dark brown, thick-walled, sometimes proliferating percurrently; phialides subhyaline to light brown, cylindrical, sometimes with a slight apical tapering, without a collarette, 11.5-21.0 x 2.0-3.0 µm. Conidia one-celled, hyaline, ellipsoid, sometimes with a single, central guttule, 4.5-6.9 x 2.0-3.0 µm.
Found on decaying wood and palm petioles. Our collections are from Costa Rica, Panama and Puerto Rico. It is also known from Malaysia. The type is from Panama. The distribution appears to be pantropical. Figure from SMH3237 (Costa Rica) and SMH3568 (Panama).
Similar Taxa Comments
Chaetosphaeria cylindrospora has robust ascomata with a strongly melanized wall that remains structurally strong even after drying. This differs from other Chaetosphaeria species where the dry ascomata are rather fragile. The wall structure does resemble that of Tainosphaeria crassiparies. Another distinctive characterisitic of Chaetosphaeria cylindrospora are the strongly clavate-shaped asci with long stipes that lack an apical ring. The size, septation and cylindrical-fusoid shape of ascospores of C. cylindrospora can be compared to the temperate-distributed C. decastyla, however, this type of ascospore is not unusual in the genus. The presence of a thin sheath surrounding the ascospores of C. cylindrospora is distinctive. Although this species was obtained in culture, no anamorph formed. An anamorph was found sparsely occurring with the ascomata of the type collection.