Flora of New Zealand Series

≡Opegrapha cinerea C.Knight & Mitt., Trans. Linn. Soc. 23: 101 (1860).

Lectotype: New Zealand. Auckland, sine loco, Charles Knight – BM [fide Hayward (1977: 576)].

Description : Flora (1985: 157).

Chemistry : TLC−, all reactions negative.

N: Northland (Bay of Islands, Whangarei, Warkworth, Great Barrier I.), Auckland (Domain, Western Springs – common throughout city), South Auckland (Mt Maungatawhiri, Whitianga, Glenbrook Steel Mill, Hamilton, Huntly, Te Kuiti), Wellington (Hutt Valley). S: Marlborough (Hapuka River), Canterbury (Christchurch), Southland (Awarua Bog). On bark of Leptospermum scoparium and Sophora microphylla and especially common on introduced trees (Platanus, Quercus, Salix) in parks, gardens and along roadsides; on decorticated wood of old fenceposts, and on weathered, outdoor (barbecue) tables and seating. The species is apparently quite tolerant of high loads of atmospheric pollutants, and is often found as the only lichen (or with traces of Chrysothrix candelaris) on trees and shrubs in highly polluted areas (alongside motorways, or around fertiliser plants and steel mills), deep in crevices of rough bark where humidity is higher and the effects of atmospheric pollution more easily withstood. Recently recorded from eastern Australia for the first time (Archer 2000b, 2003; McCarthy 2003c, 2006).

Australasian

Illustrations : Knight & Mitten (1860: tab. 11, fig. 18 – as Opegrapha cinerea); Hayward (1977: 576, fig. 9C; 577, fig. 10E).

Dictyographa cinerea is characterised by: the corticolous/lignicolous habit; the grey-white, often ±evanescent thallus; short, broad (0.5–1.0 × 0.4 mm), coal-black lirellae lacking a thalline margin but with a distinct proper exciple furrowed into 2–5 ridges and enclosing a narrow slit – the apothecia are generally widely scattered, solitary or in small groups and strongly reminiscent of scattered grains of coal-black wheat; a bitunicate ascus; branched, anastomosing paraphysoids; asci formed in loculi; muriform, colourless, thick-walled ascospores, 24–27 × 7–13 μm; and no secondary chemistry.