Flora of New Zealand Series

≡Parmelia intumescens Rebent., Prodr. Fl. Neomarch.: 301 (1804).

Description : Thallus thin to thick, areolate to continuous, 2–5(–10) mm diam., greyish white to greyish green, minutely papillate or irregular, in irregular mosaics delimited by a thin, wavy, marginal prothallus, without soredia. Apothecia sessile, scattered, solitary or occasionally in small groups, 0.1–1(–1.2) mm diam., the disc pale-brown to reddish brown, lightly white-pruinose in young fruits the pruina persisting in patches or absent at maturity. Thalline margin prominent, 0.1–0.15 mm thick, white, smooth to roughened or pruinose, entire to crenate or flexuose. Amphithecium with numerous small crystals 50–90 μm thick. Parathecium 15 μm thick, without crystals. Epithecium granular, yellow-brown, 10–15 μm thick, with small crystals. Hymenium colourless, 50–80 μm tall. Ascospores ellipsoidal to broadly ellipsoidal, 10.5–15 × 5–9 μm.

Chemistry : Thallus K+ yellow, C−; thalline margin of apothecia Pd+ deep yellow-orange; containing atranorin, psoromic acid and unidentified compound 1 (major), chloroatranorin and 2'- O- demethylpsoromic acid and unidentified compound 2 (minor) (Lumbsch et al. 1997: 152).

N: Taranaki (near New Plymouth). On stems of Berberis and Coprosma repens in roadside hedges. Still very poorly collected and understood in New Zealand (Galloway et al. 2001: 33). It is a widespread Northern Hemisphere species growing on the bark of deciduous trees and conifers in temperate areas (Lumbsch et al. 1997: 152; Ibáñez & Burgaz 1998; Nimis & Martellos 2003).

Cosmopolitan

Illustrations : Ozenda & Clauzade (1970: 518, fig. 431); Foucard (1990: pl. 150); Wirth (1995b: 478); Lumbsch et al. (1997: 150, fig. 8D); Dobson (2000: 196; 2005: 225).

Lecanora intumescens is characterised by: the corticolous habit; a pale grey-green, minutely papillate or irregular, esorediate thallus, forming irregular mosaics delimited by a thin, wavy marginal black prothallus. Apothecia are prominent, scattered, sessile, the discs plane, yellow-brown to dark- brown, white-pruinose or epruinose at maturity, and with prominent, white, Pd+ orange thalline margins. It is parasitised by the lichenicolous fungus * Lichenoconium lecanorae (Jaap) D. Hawksw. (Hafellner 2000).