Flora of New Zealand Series

Thallus foliose, lobate, dorsiventral, orbicular to irregular, usually loosely attached by a dense felt of rhizines, occasionally closely attached, to 12 cm diam. Lobes to 1 cm wide, dark greyish-blue, bluish-green or occasionally greyish-black when wet, leaden grey to pale whitish-grey when dry, adjacent, often imbricate, broadly cuneate to flabellate, apices rounded, often slightly thickened, margins ± entire, or variously minutely notched or incised or secondarily lobulate, ± conspicuously deflexed. Upper surface smooth, ± coriaceous to minutely wrinkled or in parts occasionally minutely scabrid, matt, in larger lobes few faint striae visible, arranged in parallel lines along the length of the lobes (×10 lens), often conspicuously ridged, ridges in transverse, concentric lines reflecting the attachment of rhizines to lower surface, isidiate or not, without maculae, pruina, pseudocyphellae, soralia or tomentum. Photobiont blue-green, Scytonema. Lower surface corticate, usually pale, whitish or creamish, rarely blackened, ± densely rhizinate. Rhizines simple, pale or bluish-black, complex, entangled, or in ± discrete, transverse, concentric lines, rarely projecting beyond lobe margins. Apothecia ± frequent, (rare in D. durietzii) discrete, rarely crowded, to 2 mm diam., laminal, sessile, scattered, rounded, biatorine or zeorine, disc concave at first, becoming plane or occasionally convex with age, matt, not pruinose, not gyrose-contorted, ± reddish-brown, occasionally blackened, proper margin entire, pale, sometimes blackened, sometimes with small white hairs at base, often excluded by disc or thalline margin, thalline margin present or absent. Ascospores simple, colourless, 8 per ascus, ellipsoid, uni- or biseriate, young spores usually with two oil droplets, mature spores with a somewhat roughened granular surface. Pycnidia ± frequent, wart-like, immersed, with a central black ostiole. Conidia rod-shaped.

Degelia is a Southern Hemisphere genus in the Pannariaceae with an apparent centre of speciation in New Zealand [Arvidsson and Galloway Lichenologist 13: 27-50 (1981)]. Species are epiphytic on trees and shrubs (often associated with mosses) in moist, humid sites either in full sunlight or in moderate shade. Rarely D. duplomarginata colonises mossy rocks in stands of successional shrubs such as Leptospermum. Three species are known in New Zealand.