General Description

 Colonies. On Potato Sucrose Agar (PSA) plates after 4 days growth rate varies from 5-5.8 cm, with abundant mycelium which varies from light yellow to yellowish brown, yellowish brown sporodochia are formed in colony centre, colony reverse is reddish golden. On Potato Dextrose Agar (PDA) slants after 10 days: rapid growth varies from 7.5-8.4, with white to light yellow dense aerial mycelia, reverse light yellow. "Chlamydospores" not observed. Growth on Glycerol Nitrate Agar medium (G25N) less than 2 cm diam., producing yellow aerial mycelium and orange pigmentation. On Czapek-Dox Iprodione Dichloran Agar medium (CZID), growth less than 5 cm diam., producing white aerial mycelium and orange pigmentation. On Dichloran Chloramphenicol Peptone Agar medium (DCPA) growth exceeding 5 cm diam. On tannin-sucrose agar producing phosphatase and peroxidase enzymes. Conidia. "Macroconidia" abundant in sporodochia, long, slender, straight to slightly curved, thin-walled, with elongate apical cell and well-marked foot cell, 4- to 7-septate but mostly 5-septate, 40-80 × 3.5-4 μm. "Microconidia" produced only by some isolates, scarce, from conidiogenous cells which may have one or more than one active fertile points, 1-to 3-septate, 10-50 μm. Ascomata. Perithecial, deep purple, dark blue, flesh or buff, appearing black, occurring solitarily or grouped around the lower nodes of wheat stems, each developing from a small superficial mycelial mat formed from hyphae which penetrate the epidermal cells and underlying cortical cells of the plant; in most cases a small stromatic cushion developing prior to perithecial formation and only one perithecium forming on each cushion; irregularly globose to pyriform, due to formation of large wart-like pustules on the outer wall; the outer stromatic part of the wall formed from 6-7 layers of thick-walled somewhat compressed angular cells 7-10 × 4-7 μm; those forming the 'warts' not morphologically distinct apart from being larger and more or less globose due to lack of pressure; outer wart cells measuring 10-12 × 12-15 μm. Asci. 8-spored, cylindrical to clavate, 70-100 × 9-12 μm. Ascospores. Colourless, fusoid, 1-septate, narrower at the central septum and with a somewhat larger upper cell; often remaining 1-septate and measuring 13-19 × 4-5 μm; others becoming larger and developing one or two further septa; these larger spores measuring 17-25 × 5-6.5 μm, with such variations of spore size and septation even occurring in a single ascoma. Paraphyses. Not present but the ostiolar canal lined with periphyses.