Physcia caesia (Hoffm.) Fürnr.

Data Set Maintenance: Data set compiled (Sonoran Desert Lichen Flora). Data set author(s): Bungartz F. (020120) @EXCL@ Nash T.H. Data set reviewer(s): Nash T.H.; to be published after submission; February 2002.

Nomenclature: Current taxonomic status: accepted. Taxonomic rank: species. Currently accepted name Physcia caesia (Hoffm.) Fürnr. Physcia. Physciaceae Zahlbr. (1898); Lecanorineae; Lecanorales.

Type Information: Basionym: Lichen caesius Hoffm. Type: Physcia caesia (Hoffm.) Fürnr.

Biogeography: Northern hemispheric; holarctic, arctic, and boreal (-temperate); submontane, montane, and upper montane. Continent: Asia-Temperate, Europe, and Northern America. Checklist records: Austria, Germany, Great Britain, Italy, Mexico, Sonoran Desert, and United States and Canada (continental).

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

Thallus: Foliose, subdivided into main parts, lobed; lobes horizontal; not imbricate or imbricate; separate thallus parts up to (3) mm wide. Thallus Size and Differentiation: Small; up to (5) cm in diameter. Thallus Outline: Sometimes irregular or orbicular; soon disappearing. Upper Surface: Grey (to dark grey), matt, smooth; maculate; maculae irregular; epruinose; eciliate; without hairs; not isidate; sorediate; soralia grey or pale green, laminal, subperipheral, or peripheral, often capitate, soredia coarse or farinose; not blastidiate; not schizidiate; not lobulate. Lower Surface: Present, dark grey, white, or pale grey; attached by holdfasts; rhizinate; rhizines sometimes black or grey.

Upper Cortex: Present; outer cortical layer paraplectenchymatous; inner cortical layer prosoplectenchymatous or paraplectenchymatous (the lower part gradually forming rounded. isodiametric cells). Medulla: White. Lower Cortex: Present.

Reproduction Strategy: Only known as sterile, asexually reproducing form (in Sonoran Material).

Conidiomata: Absent resp. not observed (not seen in Sonoran material, elsewhere rare).

Secondary Metabolites: Present; only in the upper part of the cortex or throughout the thallus medulla, atranorin (with zeorin and sometimes unidentified triterpenes).

Spot Tests: Present reactions. Upper surface: K + deep yellow, C –, KC –, PD + yellow; cortex: KC + deep yellow, – medulla: K + yellow; C –, KC –, PD + red (not red but yellow (atranorin in medulla)); soredia: K + deep yellow; KC –.

(report generated 13.Nov.2007)