Endoxyla sp. P1308
Anamorph: not known.
Teleomorph: stromata absent. Ascomata perithecia, 250-400 µm diam., ± globose, strongly papillate, some solitary but mostly in clusters of up to 20, initially immersed in the upper layers of bark but becoming almost superficial as the surrounding tissues decay. Ascomatal wall composed of 3-4 layers of dark brown thick-walled flattened angular cells, with simple Munk pores ca 0.5 µm diam. penetrating the cell walls, the outer layer more strongly pigmented and with thick-walled hyphae 3-4 µm in diam,, some with capitate ends, extending into the cavity between bark and wood. Interascal tissue of simple paraphyses 2.5-4 µm diam., rather sparse, very thin-walled, septate, apparently unbranched, the apices obtuse. Asci 65-80 x 6-7.5 µm, cylindrical, rather short-stalked (usually between 10 and 20 µm), thin-walled and not fissitunicate, the apex obtuse, with a rather inconspicuous apical ring that does not blue in iodine, 8-spored. Ascospores arranged ± uniseriately, ellipsoidal, 7.2-9.5 (-10.5) x 3.8-4.5 (-5.2) µm, with a conspicuous transverse septum 60-70% of the distance between apices (the shorter cell may be basal or apical), dark brown, fairly thick-walled, smooth, lacking germ pores, without a gelatinous sheath or appendages. In a proportion of asci, the ascospore development is disrupted resulting in aseptate spores or large and irregular structures that are presumably multinucleate.
Not formally assessed. Only recorded on a single occasion, but the species is externally inconspicuous and few collectors examine its substratum on a routine basis. Its distribution and conservation status need further research.
Close to Endoxyla paralella, which shares the tendency to form irregularly shaped ascospores, but "normal" ones are longer in that species, the asci have longer stalks, and it is restricted to conifer wood rather than Salix. Xylomelasma is a possible alternative placement for this species; species of that genus have small dark brown aseptate ascospores, and a proportion of those in this fungus are either aseptate or form a septum late in the developmental sequence.
In GB&I, on rotten, partially decorticated wood of Salix cinerea, on a small dead attached branch. Also recorded from rotten wood of ? Tilia sp. in southern Norway.
In GB&I, only recorded from a single locality in E Cornwall.