Flora of New Zealand Series

Description : Thallus orbicular, 3–6(–12) cm diam., loosely attached centrally, margins free, corticolous. Lobes broadly rounded, discrete to subimbricate, 1–3 cm diam. Margins entire to minutely crenate, notched or incised, often copiously sorediate and eroding back onto lower surface, sometimes ±inrolled. Upper surface dark leaden or slate-blue when wet with white maculae in well-defined reticulate patterns giving a marbled appearance to thallus (×10 lens), pale olivaceous-grey, grey-buff or brownish red when dry (maculae much less obvious in dry material), weakly to strongly reticulate-faveolate or wrinkled-plicate towards margins, ±undulate to shallowly pitted or wrinkled centrally, matt, rather fragile and papery when dry, sorediate, pseudocyphellate, without isidia or phyllidia. Soredia in scattered, erose, laminal soralia, 0.2–2 mm diam., becoming confluent and ±linear at margins and along reticulate ridges, brownish or greyish, gnarled-glomerulate, minutely styliform, pseudoisidiate, ±coarsely granular, becoming eroded-white at maturity, often densely clustered near margins and obscuring upper cortex. Pseudocyphellae occasional, scattered, inconstant, minute, pin-prick-like, yellow on ridges near lobe margins. Medulla white. Photobiont cyanobacterial. Lower surface noticeably bullate, minutely wrinkled or pitted beneath tomentum, pale yellowish buff and ±glabrous in a narrow zone at margins, or ±uniformly buff or dark red-brown to black, tomentum tufted, rather short, thin or thick, occasionally pale-buff, more often brown or black. Pseudocyphellae scattered, sparse to numerous, eroded-papillate, appearing verruciform, 0.1 mm diam. or less, decorticate area flat, white to very pale cream, level with or slightly embedded in tomentum. Apothecia and pycnidia not seen.

Chemistry : Tenuiorin, methyl gyrophorate, hopane-6α,7β,22-triol, stictic, constictic, cryptostictic and norstictic (tr.) acids.

N: Northland (Hen I.), South Auckland (S of Te Awamutu, Mangakino, Rangipo), Hawke's Bay (Kaweka Ra., Kuripapango). S: Nelson (Whangapeka Track), Canterbury (Mt Peel) [map in Galloway (1988a: 74, fig. 24)]. In cool, shaded habitats, on Leptospermum scoparium. Known also from E Australia, Ecuador and southern South America (Galloway 1988a: 72–73; 1992c; Galloway et al. 2001b; McCarthy 2003c, 2006).

Palaeotropical

Illustration : Galloway (1988a: 73, fig. 23).

Pseudocyphellaria bartlettii is characterised by: broadly rounded lobes with conspicuous, photobiont-free areas developed on the upper surface as well-defined reticulate maculae (×10 lens); a white medulla; a cyanobacterial photobiont; white pseudocyphellae on the lower surface; laminal, erose soralia on the upper surface containing brownish or greyish, pseudoisidiate to coarsely granular soredia; it has a complex chemistry of depsides, depsidones and hopane-6α,7β,22-triol, but lacks the pigments pulvinic acid, pulvinic dilactone and calycin.