Schizoxylon sp. P3971
Anamorph: not known.
Teleomorph: ascomata apothecia, becoming ± superficial, 340-520 µm diam., the margin very thick, strongly white-pruinose, involute, not strongly fissured, the disc deeply urceolate, reddish orange. Margin in cross section 30-35 µm thick, not containing host tissue, the wall of hyaline frequently branched interwoven hyphae 2-2.5 µm diam., forming a compact layer adjoining the periphysoids in the lower and inner portions of the margin, becoming more loosely interwoven in the upper and outer portions, abundantly crystalliferous on the exterior, the crystals small and uniform, hyaline, copious yellow pigment released in KOH. Periphysoidal layer composed of ± isodiametric cells, the innermost row elongate, with free ends. Subhymenium ca 40 µm thick, hyaline, of small angular cells. Paraphyses numerous, filiform, ca 1 µm diam., rarely branched, the apices somewhat irregular (propoloid), not staining in iodine. Asci 105-130 x 8-11 µm, thick-walled when young, the cap 4-6 µm thick, pierced by a narrow pore, 8-spored. Ascospores arranged in a single fascicle, sometimes partially helically coiled, not fragmenting, 90-105 x 2-2.5 µm, filiform, multiseptate, the individual cells 5-7 µm long, hyaline, smooth-walled.
Not formally assessed; only known from one or two collections, but perhaps overlooked.
Characterized by its copiously white-pruinose and crystalline apothecia that produce copious bright yellow pigments in KOH, the fairly short asci containing eight multiseptate ascospores almost as long at the asci.
Schizoxylon berkeleyanum is also K+ yellow and appears similar to this species, but it has ascospores that fragment into part-spores and an apparently less well-developed exciple.
On a dead fruit-body of a bracket fungus (possibly Stereum sp.).
Recorded from a single site in VC3 S Devon. Another collection that may be this species has been reported on a dead branch of Picea abies; that has somewhat shorter ascospore segments but this may be due to minor differences in septation.