Flora of New Zealand Series

Parmelia subrudecta Nyl., Flora 69: 320 (1886).

Thallus orbicular to spreading, loosely attached, 5-10(-15) cm diam., corticolous or saxicolous. Lobes rounded, dissected, crowded, margins sinuous, entire, darkening, becoming sorediate. Upper surface greenish-grey to greenish-blue, matt, shining at margins which are often suffused brownish, conspicuously wrinkled, with scattered, punctiform pseudocyphellae towards centre, becoming copiously sorediate. Soredia irregular, coarse, granular, greenish-brown to blackish, derived from pseudocyphellae. Lower surface pale yellowish-buff or buff-brown or whitish, smooth or wrinkled, shining, sparsely rhizinate. Rhizines simple, pale, often to the margins. Apothecia maculae and pycnidia not seen in New Zealand material. Chemistry: Cortex K+ yellow; medulla K-, C+ red, KC+ red, Pd-. Lecanoric acid and atranorin.

N: South Auckland to Wellington. S: Nelson to Southland. St: Lowland, widespread, often in disturbed habitats.

Cosmopolitan

P. subrudecta is a rather polymorphic species, related to P. borreri but differing in the colour of the lower surface, the distinctly non-pseudocyphellate marginal zone, and in having lecanoric acid as the major medullary constituent. It is widely distributed throughout New Zealand and is common in urban areas on introduced trees in parks and gardens as well as on fenceposts in country areas. It is a good indicator of disturbed, eutrophic habitats and appears to be moderately tolerant of high levels of atmospheric pollution, being the most common foliose lichen in polluted areas such as Christchurch city.