Flora of New Zealand Series

Description : Thallus thin to thick, rimose–areolate or continuous to verrucose–areolate, whitish grey to greyish green, epruinose. Soredia absent. Prothallus whitish grey or absent. Apothecia sessile, 0.8–3 mm diam., discs carneous to pinkish, heavily grey-white-pruinose, plane to convex. margins prominent, thick, persistent, smooth, entire or flexuose, concolorous with thallus. Cortex absent, pseudocortex 45–105 μm thick, inspersed with small crystals, photobiont containing part of amphithecium with numerous small crystals, 25–75 μm thick, parathecium with small crystals, c. 15 μm thick. Epithecium 10–15 μm thick, grey-brown granular with small crystals. Hymenium hyaline 55–95 μm tall. Ascospores ellipsoidal to broadly ellipsoidal, 9–15 × 5.5–9.5 μm.

Chemistry : Major compounds: atranorin, ±norstictic, ±protocetraric and ±virensic acids; minor compounds: chloroatranorin, ±connorstictic, ±conprotocetraric, ±norstictic, ±protocetraric, ±salazinic, ±stictic and ±virensic acid (Lumbsch et al. 1997b). Five distinct chemodemes are known, three of which are recorded from New Zealand (Lumbsch et al. 1997b: 147–148).

S: Canterbury (Arthur's Pass, Cass, Hanmer Springs, Lake Lyndon), Otago (Kea Basin, Rees Valley, Green Peak, Silver Peaks, Maungatua summit, Wangaloa Hill, Conical Hills), Southland (Waituna Lagoon). On bark of both native (Dracophyllum longifolium, Nothofagus solandri var. cliffortioides) and introduced trees (Galloway et al. 2001a: 29) and on lignum (fenceposts). Also known from Africa, North and South America, South and East Asia, Hawai'i, and Australia (Imshaug & Brodo 1966; Esslinger & Egan 1995; Lumbsch et al. 1997b; Brodo et al. 2001; McCarthy 2003c, 2006; Lumbsch & Elix 2004; Ryan et al. 2004b: 203–204). Brodo et al. (2001: 376–377) accept several named subspecies in North America, following Imshaug & Brodo (1966). Still rather poorly known and collected in New Zealand. Earlier records of L. pallida (Schreb.) Rabenh. [=L. albella (Pers.) Ach.] (Galloway 1985a: 217; Galloway 1992d) refer to L. caesiorubella.

Cosmopolitan

Illustrations : Hale & Cole (1988: 202, fig. 67C); Lumbsch et al. (1997b: 141, fig. 5E, F; 144, fig. 5A–F); Flora of Australia56A (2004: xii, pl. 8).

Lecanora caesiorubella is characterised by: the corticolous/lignicolous habit; the grey-white to greyish green, epruinose, esorediate, continuous to verrucose–areolate thallus; large, sessile apothecia, 0.8–3 mm diam., with a pinkish, heavily grey-white-pruinose disc (C−) and a thick, flexuose thalline exciple; ellipsoidal to broadly ellipsoidal ascospores, 9–15 × 5.5–9.5 μm; and a complex and rather variable chemistry containing atranorin and norstictic acid (see above). It is distinguished from L. carpinea by the larger apothecia and the lack of chromones (C+ yellow) in the apothecial discs.