Delitschia bispora (All Fungi)
Anamorph: absent.
Teleomorph: Stromata absent. Ascomata 280-350 x 250-300µm, perithecial, pyriform, the neck only slightly papillate, the ostiole wide (to ca 100µm), pale to mid brown, the pigmentation sometimes irregular. Peridium membranous, composed of an outer layer of rather irregular cells intermediate between textura angularis and epidermoidea with cells to 10µm diam, fairly thick-walled, not strongly pigmented, and inner layers of ± hyaline tissue. Interascal tissue well-developed, composed of copious anastomosing trabeculate pseudoparaphyses. Asci clavate, short-stalked, 115-135 x 25-33µm, thick-walled when immature, rather thin-walled when mature, ? fissitunicate, 2-spored. Ascospores 38.5-44 x 27-32µm, very strongly constricted at the septum, the upper cell slightly wider and more rounded than the lower, very thick-walled (to ca 2.5µm), often slightly inaequilateral, with a conspicuous straight parallel germ slit in each cell, the two slits arranged at around 90° to each other; mucous sheath not seen.
Luck-Allen & Cain (1975) considered this species to belong to Sporormiella, interpreting the asci as originally one-spored. Quite possibly neither Delitschia nor Sporormiella are appropriate placements. The two propagules are separate from a very early stage of development, and the appearance at maturity of asci containing a single 3-septate ascospore may be due to the two spores being crushed aginst each other as they increase in size. The original genus Delitschia is chosen here as the part-spores frequently do not separate at maturity and the ascospores are very large and usually inaequilateral - all features typical of that group rather than Sporormiella.
On a test block of Fagus wood immersed in the cooling water of a power station.
England: Yorkshire; only known from the type collection.