Phaeopyxis
Type : * Phaeopyxis punctum (A.Massal.) Rambold, Triebel & Coppins [* Nesolechia punctum A. Massal.]
Description : Lichenicolous or ?algicolous (on decorticated wood). Ascomata apothecia, small, brown-black, ±distinctly marginate, rounded. Exciple dark-brown to dark violet-brown to carbonised. Hypothecium pseudoparenchymatous with thick-walled hyphae, brown to violet-brown or colourless to mottled dark-brown. Hymenium colourless to pale-brown; epithecium dark-brown, violet-brown to brown-black. Hamathecium of paraphyses, septate, sparingly branched and anastomosing, 1–2 μm thick, apices scarcely enlarged. Pigment of hypothecium, excipulum and epithecium coarsely granular. Asci clavate to subcylindrical, with a short stalk, 8-spored; ascus wall at apex to 3 μm thick, laterally to 1.5 μm thick, I+ pale-bluish or I−. Ascospores simple, colourless, ellipsoidal to ovoid, smooth. Conidiomata unknown.
Phaeopyxis is a genus of five mainly lichenicolous species included in the Helotiales incertae sedis (Triebel 1989; Rambold & Triebel 1990; Hawksworth 2003; Lawrey & Diederich 2003; Diederich 2004h; Eriksson et al. 2004). It is characterised by asci typically showing a distinct, concave apical delimitation of the inner ascus wall (Rambold & Triebel 1990: 382, fig. 3A–D), and a dark, quite coarsely granular pigmentation (K+ violet-brown) of the exciple, hypothecium and epithecium. It has an ascus type similar to that in Leotia Pers., but differs in developing no stipitate ascomata, more conglutinate paraphyses, and a granular pigmentation. Genera in the Agyriaceae also have asci with an apical dome shaped as in Phaeopyxis and Leotia, but with a distinct amyloid cap-like structure in the tholus. The species in the genus are separated from each other mainly by spore size and shape, the amyloid reaction of the ascus wall (seen in dilute Lugol's I solution), and by their hosts or substrata. Taxa are known as parasites of several species of Cladonia, from Paraporpidia leptocarpa, Trapeliopsis gelatinosa and from decorticated wood (Triebel 1989; Rambold & Triebel 1990). One species is recorded from New Zealand as a parasite on squamules of Cladonia ustulata from Campbell I. (Nylander 1876; Rambold & Triebel 1990).
