Pseudocyphellaria coerulescens (Mont.) H.Magn.
Sticta coerulescens Mont., Annls Sci. nat. Bot. sér. 3, 8: 306 (1852).
Thallus orbicular to spreading, often rosette-forming, 5-10(-12) cm diam., ± closely attached or often with margins ± free. Lobes rounded, contiguous to imbricate or shallowly laciniate, undulate, margins entire or ± phyllidiate, ± crisped-sinuous, subascendent, variously notched or incised, occasionally with pock-like to ± linear, yellow pseudocyphellae. Phyllidia occasional, small, 0.1-0.6 mm tall, fragile, denticulate to subcoralloid, concolorous with thallus or brownish above, yellow-gold, corticate or decorticate below, marginal, often dense in older parts, rarely laminal. Upper surface dark bluish-purple when wet, pale blue or greyish-fawn when dry, conspicuously maculate (×10 lens) especially at apices and margins of lobes, shining, smooth or shallowly faveolate, without soredia, isidia or pseudocyphellae. Medulla yellow. Photobiont blue-green. Lower surface pale yellowish-buff, at margins darkening towards centre, uniformly short-tomentose-pubescent, tomentum pale buff, fine, silky. Pseudocyphellae sparse, yellow, convex, projecting above tomentum, 0.1-0.3(-0.5) mm diam., round to subirregular. Apothecia not seen. Chemistry: Pulvinic dilactone, pulvinic acid, calycin, and a mixture of stictanes.
S: Nelson (Lake Rotoiti), Canterbury (Lewis Pass, Boyle River, Banks Peninsula). On Dacrycarpus dacrydioides, Leptospermum scoparium bark, rarely on Nothofagus bark at treeline, lowland to subalpine, still rather poorly collected.
Austral
Although there are certain differences (such as chemistry, and the occasional presence of phyllidia) between New Zealand and South American populations of P. coerulescens (the type is from southern Chile) the name is used here until more collections allow the true nature of the New Zealand populations to be accurately assessed. Although the species appears similar to P. ardesiaca and is often sympatric with it, the chemistry differs (P.W. James pers. comm.).
It is also not yet certain whether the phyllidiate specimens should be referable to a separate species.
