Pyxine petricola Nyl.

Data Set Maintenance: Data set compiled (from Sonoran Desert Lichen Flora). Data set author(s): Bungartz F. (02-04-25). Data set to be published after submission; February 2002.

Nomenclature: Current taxonomic status: accepted or basionymous. Taxonomic rank: species. Currently accepted name Pyxine petricola Nyl. Pyxine. Synonyms: Pyxine devertens (Nyl.) Vain.
Pyxine pringlei Imshaug; Physciaceae Zahlbr. (1898); Lecanorineae.

Type Information: Basionym: Pxine petricola Nyl. Type: Pyxine petricola Nyl.

Biogeography: Subtropical (scattered collections) and pantropical; colline and submontane. Continent: Northern America. Checklist records: Mexico, Sonoran Desert, and United States and Canada (continental).

Ecology: Biotroph; lichenized; lignicolous or corticolous; episubstratic; growing sun-exposed or partially shaded; under conditions which are dry or moist; substrate non-calciferous.

Thallus: Foliose (firmly appressed), subdivided into main parts, lobed (firmly appressed); lobes horizontal; plane; separate thallus parts.7-1 mm wide. Thallus Size and Differentiation: Up to 5 cm in diameter. Thallus Outline: Orbicular. Upper Surface: Grey, almost white, or grey-green; pruinose; pruina scarce; whitish (often glistening); patchy (rarely punctiform); sparsely pseudocyphellate (true pseudocyphellae); pseudocyphellae sometimes reticulate, mostly peripheral, submarginal or marginal (usually restricted to the peripheral parts of the lobes); eciliate; without hairs; not isidate or isidiate; not sorediate; not blastidiate; not schizidiate; not lobulate. Lower Surface: Present, black or grey, black in the centre, grey (towards the lobe tips) along the margin, firmly attached attached; attached by holdfasts (true rhizines); rhizinate; rhizines abundant, black, branched, sparsely furcate; not sorediate; not tomentose.

Upper Cortex: Present; outer cortical layer paraplectenchymatous (formed by anticlinal hyphae); inner cortical layer prosoplectenchymatous or scleroplectenchymatous (formed by periclinal hyphae). Lower Cortex: Present.

Reproduction Strategy: Rarely with sexual (and possible asexual) stages. Ascocarps: Apothecioid (cocoes-type), orbicular, forming all across the thallus surface, soon sessile or substipitate (on a distinct internal stipe), sparse, .5-1.5 mm in diam.. Margin: Lecanorine (when young) or lecideine/biatorine (margin excluded in older apothecia), smooth, excluded, distinct; not sorediate; not isidiate; not ciliate; not hirsute. Disk: Plane; black; epruinose. Exciple: Carbonized (margin excluded in older apothecia). Epithecium: Apical cells brownish blue (not brown: bluish black), cell pigment reacting with 10% KOH (K+ purple). Hypothecium: White (lower part of stipe) or brownish red (rose-red or orange-red, upper part of stipe).

Asci: Dehiscence lecanoralean.

Ascospores: Dirinaria-type, c. 8 per ascus, spores 8 per ascus, ellipsoid, 14-19 µm long, 5-7.5 µm wide; septa present; transversally septate; 1-transversally septate; wall apically thickened, subapically not thickened, thickened at the septum, becoming pigmented, dark brown or middle brown (at maturity).

Conidiomata: Present.

Conidiophores: Vobis-type VI. Conidia: Bacilliform; 3-4 µm long; 1 µm wide.

Secondary Metabolites: Present; only in the upper part of the cortex, lichexanthone, metabolite(s) of unresolved identity: present (medulla with terpenes).

Spot Tests: Absent (but upper part of stipe K+ red, KC+ purple) reactions. Upper surface: C –, KC –, PD – cortex: KC –, –, PD – medulla: K – or + yellow changing to red (upper part of the stipe K+ purple, lower part K-); C –, KC – (entire medulla including stipe), PD –.

(report generated 13.Nov.2007)