Vialaea insculpta  

Anamorph: not known.
Teleomorph: ascomata scattered over the surface of the host. visible as poorly defined rings of slightly darker epidermal tissue, with the included tissue usually slightly paler than the surrounding tissue, and a small central tear in the host tissue through which the ascospores are released, the ostiole rarely protruding, the fungus not strongly raising the host surface. Clypeus 300-500 µm diam., 100-150 µm thick. rarely coalescing, roughly circular in surface view, composed of dark brown thick-walled hyphae, which are rather diffuse towards the edge of the clypeus. Ascomata perithecia, 280-400 µm diam., deeply immersed, the body roughly sphericaL sometimes somewhat flattened, the lower half often invaginating when dry, fairly long-necked, the neck 200-500 µm tall, 80-100 µm diam., dark brown to black. Peridium 20-30 µm thick, composed of several layers of slightly flattened strongly melanized thick-walled textura globulosa 10-15 µm diam., with occasional pores 0.75-1 µm diam. between cells. Periphyses copious, 2-3 µm in width, hyaline, fairly thin-walled. Interascal tissue of paraphyses 12-22 x 5-9 µm, few in number, probably at least sometimes deliquescent at maturity, much shorter than the asci, extremely thin-walled, composed of strongly inflated cells. Asci developing from croziers, 158-182 x 17-26 µm, cylindric-ellipsoidal to ± cylindrical, sometimes tapering towards the apex, usually short-stalked, fairly thin-walled except near the apex at all stages of development, the apex obtuse, becoming truncate or even everted after spore release with a subapical ring 3-4 µm diam. and 3.5-9.5 µm thick, a small region ca 1 µm thick at the base of which blues strongly in iodine, the edge of which projects slightly downwards into the ascus cavity, 8-spored. Ascospores arranged biseriately to fasciculately, sometimes weakly helically coiled, 78-94 x 5.5-6 µm, strongly isthmoid, the end portions fusiform, tapering gradually to an acute tip and towards the central portion, which is 3-4 µm diam.; mostly 1- or 2-septate, the septum in 1-septate spores not always exactly at the narrowest point, the septa close together in 2-septate spores, hyaline, smooth-walled. One-celled ascospores occur in some collections; these are usually less strongly constricted in the central portion.