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Family: XylariaceaeGenus: Anthostomella
Anamorph: not known.
Teleomorph: stromata absent. Ascomata perithecia, ± globose, 220-300 µm diam. with a very short ± truncate neck; scattered or in clusters of 2-3 under a common clypeus, the base immersed in the mesophyll and the neck hardly erumpent from the upper surface of the leaf. Clypeus diffuse, rather variable in extent, ranging from an inconspicuous collar surrounding the neck to a ± circular mat of hyphae 150-270 µm diam. inserted between cuticle and upper epidermis of the plant host, sometimes merging with neighbouring colonies to form larger blackened areas on the host surface. Ascomatal wall black, leathery, composed of an outer layer of irregular epidermoidal cells, several layers of strongly pigmented thick-walled angular cells to ca 12 µm diam., and an internal layer of almost hyaline flattened tissue. Interascal tissue of thin-walled unbranched paraphyses 1.5-2 µm in diam, evanescent at maturity. Asci 100-110 x 8-10.5 µm [88-91 x 8-10 µm fide Francis 1975], cylindrical, the width dependent on ascospore orientation, the apex rounded and the basal region short and tapered, rather thin-walled; apical ring hardly visible in lactic acid but staining blue in Lugol's iodine, annular, ca 3.5 µm diam. and ca 1 µm in height; 8-spored. Ascospores arranged uniseriately, often partially or entirely obliquely, 13-14.5 x 6-7 µm [12-15 x 6-7 µm fide Francis 1975], aseptate, fusiform, hardly flattened laterally, dark chocolate brown when mature, smooth-walled, with an conspicuous ± straight germ slit on one narrow face, without a gelatinous sheath or appendages.