Flora of New Zealand Series

Lichen caesius Hoffm., Enum. lich. eur.: 65 (1784).

Thallus orbicular to spreading, closely attached, to 6 cm diam., saxicolous. Lobes irregularly or pinnately branched, ± convex often imbricate, rounded at apices, 0.5-2 mm wide. Upper surface grey or whitish-grey, often greyish-pruinose, conspicuously white-maculate, sorediate. Soralia laminal, occasionally marginal, scattered, often confluent, soredia granular, white. Lower surface pale brown to brown, rhizinate. Rhizines sparse, pale. Apothecia (not seen in New Zealand material) rare, sessile, to 1.5 mm diam. Ascospores 17-24 × 7-11 µm. Pycnidia immersed. Conidia 4-5 × 1 µm. Chemistry: Cortex and medulla K+ yellow. Atranorin, leucotylin, zeorin and two unidentified compounds.

S: Canterbury (Weka Pass, Cave Stream, Ashburton Gorge, Rangitata Gorge), Otago (Central Otago), Southland (Clifden). Although poorly collected it is known from coastal rocks and asphalt footpaths in Otago and Southland, as well as from limestone rocks and schist and greywacke in drier eastern parts of Otago and Canterbury.

Cosmopolitan