Pyxine cocoës (Sw.) Nyl.

Data Set Maintenance: Data set compiled (from Sonoran Desert Lichen Flora); to be published after submission; February 2002.

Nomenclature: Current taxonomic status: accepted. Taxonomic rank: species. Currently accepted name Pyxine cocoës (Sw.) Nyl. Pyxine. Physciaceae Zahlbr. (1898); Lecanorineae.

Type Information: Basionym: Lichen cocoës Sw. Type: Pyxine cocoës (Sw.) Nyl.

Biogeography: Subtropical (few collections) and pantropical; coastal, colline, rarely submontane, and montane (rarely). Continent: Africa, Europe (Laurimacaronesia), Northern America, and Southern America. Checklist records: Mexico, Sonoran Desert, and United States and Canada (continental).

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

Thallus: Foliose (firmly appressed), subdivided into main parts, lobed (firmly appressed); lobes horizontal; subconcave or usually plane or subconvex; separate thallus parts narrow; .4-.8 mm wide. Thallus Size and Differentiation: 3-4-(10) cm in diameter. Thallus Outline: Orbicular. Upper Surface: Grey, white (almost), or light brownish yellow; pruinose; pruina patchy (often glistening); pseudocyphellate (pseudocyphellae); pseudocyphellae sometimes reticulate, usually peripheral, submarginal; eciliate; without hairs; not isidate; always sorediate; soralia laminal or subperipheral, linear (initially narginal fissural soredia, later orbicular and laminal), soredia coarse or rarely farinose; 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 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, orbicular, forming all across the thallus surface, soon sessile or substipitate (on a distinct internal stipe), sparse, .4-1.4 mm in diam.. Margin: Lecideine/biatorine (when margin excluded), smooth, excluded, distinct; not sorediate; not isidiate; not ciliate; not hirsute. Disk: Plane; black; epruinose. Exciple: Carbonized (when margin excluded). Epithecium: Apical cells brownish blue (not brown: bluish black), cell pigment reacting with 10% KOH (K+ purple). Hypothecium: White or brownish red (upper part of stipe).

Asci: Dehiscence lecanoralean.

Ascospores: Dirinaria-type, c. 8 per ascus, spores 8 per ascus, ellipsoid, 15-18 µm long, 6-7 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 – C –, KC –, PD –.

(report generated 13.Nov.2007)