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Family: ValsaceaeGenus: Leucostoma
Anamorph: conidiomatal locules formed within the stromata, often multilocular, convoluted and radiating from the centre, probably preceeding perithecial formation. Conidiophores 10-18 µm long, hyaline, septate, branched irregularly at the base and above, formed from the inner cells of the locule walls. Conidiogenous cells not clearly distinct morphologically from the conidiophores, usually formed as long distinct branches, straight, hyaline, smooth, proliferating percurrently, collarette and periclinal thickening inconspicuous. Conidia 3-8 x 1(-2) µm, sometimes forming red tendrils, cylindrical to allantoid, hyaline, thin-walled, aseptate, without guttules, often extruded as globose droplets or tendrils.
Teleomorph: stromata 1.5-2 mm diam., the exposed part flat, prominent, erumpent, containing 3-10 (-20) ascomata. Ectostromatic disc 400-500 µm diam., white, dotted with black perithecial necks. Entostroma white to greyish, composed of interwoven hyphae with some host cells intermixed in the lower part, well-developed, delimited by a conspicuous black stromatic zone line 40-50 µm thick, particularly prominent beneath the perithecia. Ascomata perithecia, 250-500 µm diam., ± globose with elongate necks 300-900 µm long and 70-80 µm wide µm diam. at the base, black, upright to oblique, necks converging, emergent through the disc but only just exceeding the upper surface. Peridium 12-15 µm thick, composed of dark, thick-walled angular cells. Interascal tissue absent, but neck periphysate. Asci (35-) 40-50 (-61) x (5-) 8-9 (-12) µm, cylindrical-clavate with a tapering base, apically thickened, with a refractive I- apical ring, becoming detached within the perithecial cavity, mostly 8-spored. Ascospores (7.5-) 10-13 (-18) x (1.5-) 2-2.5 (-4) µm, allantoid to cylindrical, hyaline, aseptate, smooth- and thin-walled, without a gelatinous sheath or appendages.