Flora of New Zealand Series

Holotype: New Zealand. South I., Westland, Stillwater near Greymouth. On Dacrycarpus dacrydioides, sine datum, J.K. Bartlett 25703c – BM. Isotype – AK.

Description : Thallus squamulose–subfoliose, irregularly spreading, rosette-forming, congested to ±flat, 0.5–2.5(–4) cm diam. Lobes short, broadly laciniate subcanaliculate in central parts to ± plane or convex, 1–4 mm wide, thick, coriaceous, tough. Margins slightly thickened and curled under at lobe apices, rounded, entire or shallowly notched–incised to occasionally minutely lobulate, often ±wavy, ascending to strongly involute, developing prominent blue-grey to brownish, limbiform soralia on the upturned lower surface, often eroding and leaving large whitish areas at margins of lower surface; soredia coarsely granular to minutely coralloid or glomerulate, 0.1 mm diam. or less, rarely becoming small-lobulate. Upper surface dark blue-green when wet, pale-grey to glaucous chestnut-brown when dry, matt to shining, shallowly papillate centrally, distinctly areolate–scabrid at margins and occasionally silky white-tomentose at lobe apices. Lower surface white to cream or pale-buff, delicately arachnoid, without rhizohyphae. Apothecia and pycnidia not seen.

Chemistry : Medulla P+ yellow-orange; containing vicanicin and norvicanicin (Huneck & Yoshimura 1966: 344, 352).

N: South Auckland (Slipper I., Hauhungaroa Ra.). S: Westland (Stillwater), Canterbury (Boyle River nr Lewis Pass), Otago (Chinaman's Flat, Dart Valley, Routeburn, Dunedin, Botanic Gardens). Corticolous, s.l. to 650 m. A characteristic but very widely scattered, lowland forest species most often found among bryophytes and other lichens in moderate to deep shade at or near forest margins, or from trees and shrubs in frost-flat clearings, rarely in urban environments. It is a rather rare epiphyte of Coprosma, Dacrycarpus, Leptospermum scoparium, Nothofagus solandri var. cliffortioides, and on a willow trunk by the Leith Stream in shady crevices of moist, old, spongy bark. Known also from Tasmania where it is rare (Jørgensen & Galloway 1992b: 300; McCarthy 2003c, 2006).

Australasian

Illustration : Jørgensen & Galloway (1989: 298, fig. 2).

Specimens of Fuscoderma limbatum show little variation and are often found as scattered and rather few individuals among other lichens. Superficially it appears to be a slightly more leafy, sorediate version of F. applanatum, but it has a different chemistry. It is distinct from Leioderma sorediatum which has an arachnoid upper surface, and no chemistry.