Diaporthales » Gnomoniaceae » Gnomonia¬†

Gnomonia papuana

Gnomonia papuana Sivan. & D.E. Shaw


Sexual morph: Perithecia were globose, immersed, black, smooth, 120-280 µm broad with long necks protruding a little above the water surface in the petri dish. Necks cylindrical, straight or slightly curved, 440-1100 µm long, 15-66 µm wide, black, composed of dark brown septate hyphae 2-4 µm thick, running longitudinally in the shaft, less coloured towards the tip, and lined on the inside with hyaline periphyses. Asci obovoid, 19-27 (mostly 21-23) ´ 4-7.5 µm, unitunicate, 8-spored, with an apical ring apparatus which appears as two adjacent refractive areas each about 0,6 µm tall, from 0.6-1.2 µm from the tip, not staining blue in iodine. Ascospores arranged parallel to one another in the ascus, straight to slightly curved, cylindrical, slightly tapered to the rounded tip, slightly more tapered to the base, hyaline, one septate, guttulate, 17-23 ´ 0.9-1.2 µm. When stained in Giemsa after hydrolysis with N HCI at 60 DC, the ascospores showed one nucleus per cell. Asexual morph: Conidiophores wide spreading, verticillately branched, smooth-walled, septate, hyaline, 1.5-3 µm thick. The ultimate branches of the whorls consist of two cells, of which the smaller basal cell almost always possesses a smaller phialidic conidiogenous cell just below the septum separating the upper, longer phialidic conidiogenous cell. Occasionally two to three whorls arise as terminal phialides. Phialidic conidiogenous cells are hyaline, tapering towards the spore forming apex, 3-8.5(18) ´ 2-3 µm, Conidia are enteroblastic, produced in slanting oblique chains with their ends lying one over the other and these conidia sometimes occur in short chains when they are not fully detached from one another. Conidia are hyaline, slightly greenish in mass, smooth, fusiform, with more or less tapered ends, one-celled, guttulate, 4.5-7.5 ´ 1.5-2 µm, when stained with Giemsa after acid hydrolysis show one nucleus per conidium. (Description based on Sivanesan & Shaw, 1977)

Distribution: Papua New Guinea, on submerged leaves (Sivanesan & Shaw 1977).

Notes: Holotype IMI 197503. Sequence data is not available.