Flora of New Zealand Series

≡Parmelia albata F.Wilson, Vict. Nat. 6: 69 (1889).

Description : Thallus orbicular to irregular, very variable in size, usually 5–10 cm diam., loosely attached. Lobes mostly broadly rounded, apices rounded and incised. Upper surface whitish grey, darkening at apices, usually without pruina; sorediate. Soralia laminal, maculiform initially as small pustules or cracks, joining to form larger, confluent patches. Soredia granular, whitish. Lower surface white to ash-grey, rarely darker, with numerous pale to grey-black, simple rhizines. Upper and lower cortices paraplectenchymatous. Apothecia rare (not seen in NZ material) to 3 mm diam., thalline margin smooth to crenulate, sometimes dissolving into soredia. Ascospores Pachysporaria -type, (17–)20–25 × 8–12 μm. Pycnidia rare.

Chemistry : Upper cortex and medulla K+ yellow; containing atranorin and zeorin.

N: Northland (Radar Bush), Gisborne (Mt Taitai), Taranaki (Stratford). S: Nelson (Kaihoka, Roding River Valley), Otago (Makarora). On both native and introduced trees, especially common on Acer pseudoplatanus, also on volcanic rocks. Known also from East and South Africa (Moberg 1986b, 2004b; Swinscow & Krog 1988), South America where it appears to be rare (Moberg 1990; Scutari 1995b; Galloway & Quilhot 1999; Calvelo & Liberatore 2001), Hawai'I, and Australia (Hale 1963; Elix & McCarthy 1998; Moberg 2001; McCarthy 2003c, 2006). The non-sorediate counterpart species, P. dilatata, is so far not known from New Zealand.

Palaeotropical

Illustration : Moberg (1986b: 852, fig. 10).

Physcia albata is characterised by: the corticolous habit; the broad, rounded lobes with entire margins; the smooth, matt, epruinose upper surface; and soralia in spreading patches, arising from eroding pustules or papillae and spreading more widely over lamina, often exposing areas of white medulla beneath.