Vizella metrosideri P.R. Johnst. 2000
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Descriptions
Vizella metrosideri P.R. Johnst. 2000
Vizella metrosideri P.R. Johnst. 2000
Fruiting bodies appear to arise from the sides of the hyaline cells, where a thick, dark septum forms between part of the side wall of the cell and the adjacent cell of the fruiting body. Ascomata somewhat flattened, circular in outline, 0.15-0.2 mm diam., intracuticular or subcuticular; upper wall up to 10 µm thick in vertical section, comprising 1-3 layers of angular cells 4-6.5 µm diam. with walls thick, dark brown; in face view cells of upper wall more or less cuboid, 6.5-7.5 µm diam., arranged in quite regular, radiating rows; lower wall more or less lacking, comprising remains of a single layer of cells that split as ascomatal cavity forms; in centre of ascoma is a column of hyaline, cylindric cells which extends between base and upper wall, the wall above this column breaks down to form a single, central, round ostiole; ascogenous hyphae develop in a ring near outer perimeter of ascoma, the developing asci lying more or less flat, orientated inward toward centre of ascoma.
Asci in water 70-80 x 14-16 µm, more or less cylindric, uniformly thin-walled, 8-spored, spores clustered near top of ascus; in 3% KOH asci slightly shorter, 60-70 µm long, spores clustered near base of ascus, with wall very thick at apex, with narrow central pore; dehiscence fissitunicate.
Ascospores 11.5-13(-14) x 5-6 µm (mean 12.4 x 5.6 µm, n = 33), oblong or tapering slightly to base, ends broadly rounded, wall smooth, slightly thickened, dark brown with a broad hyaline band in upper third of spore, 0-septate.
Paraphyses probably lacking; in squash mounts irregularly branched, paraphysis-like elements are seen amongst the asci, but these appear to arise from a different hyphal system to that holding the asci, and they may form the central column of sterile tissue.
Conidiomata somewhat flattened, circular in outline, 0.15-0.2 mm diam., intracuticular or subcuticular; upper wall up to 15 µm thick in vertical section, comprising 1-3 rows of angular cells 5-6.5 µm diam. with walls thick, dark brown, inside of wall lined with conidiogenous cells; in face view, cells of upper wall more or less cuboid, arranged in regular, radiating rows; lower wall more or less lacking, comprising lower wall of a layer of cells that appears to break as ascomatal cavity forms. Conidiogenous cells initially ampulliform, 4.5-6.5 µm diam., developing narrow necks up to 12 µm long with age, necks with a series of annellations due to percurrent proliferation. Conidia 8.5-9.5(-10.5) x 4.5-5.5 µm (mean 9.4 x 4.9 µm, n = 34), ovoid, tapering toward apex, ends broadly rounded, hyaline, 0-septate.