A New Graminicolous Species of Xylaria

Abstract

A new species in the Hypoxylaceae found growing on culms of Spartina patens is described as Xylaria psamathos. Immature ascospores lack appendages and are binucleate. Mature ascospores are uninucleate due to degeneration of one nucleus. The anamorph is sympodioconidial in a compact palisade. At the sandy margin of a North Carolina salt marsh, a fungus was discovered whose black, stipitate stromata grew from the buried, dead culms of Spartina patens (Ait.) Muhl. (FIG. 9c). The stromata were teleomorphs possessing characters of the Hypoxylaceae. The one-celled, brown ascospores had germ slits and the ascospores were contained within asci whose apical rings blued in Meltzer's reagent (FIGS. 5, 6, 9a). Appendages were lacking on immature ascospores examined by fluorescence microscopy, using the technique of Rogers (1975) (FIG. 4). The mitotic sequence within the ascospores was observed by staining with haematoxylin (technique by Rogers and Malmgren, 1977). Newly delimited ascospores are uninucleate. Following mitosis, immature ascospores are binucleate (FIG. 8). As maturation progresses, indicated by the darkening of the ascospores, one nucleus degenerates (FIG. 7). This mitotic sequence is, apparently, widespread among the hypoxylaceous fungi (Rogers and Malmgren, 1977; Rogers and Stiers, 1974 and references cited therein). The black surface of some of the stromata in the North Carolina collection cracked open and exposed inner tissues. The entostroma of one stroma differentiated to produce an anamorph (FIG. 9d) with conidia produced holoblastically in sympodial fashion. The conidiophores formed a compact palisade on the surface of the stroma. This anamorph type is associated with the genus Xylaria.