Pseudocyphellaria dissimilis (Nyl.) D.J.Galloway & P.James
Stictina fragillima var. dissimilis Nyl., Syn. Meth. Lich. 1 (2): 336 (1860).
Thallus linear-laciniate, suborbicular to spreading, 5-10(-20) cm wide, loosely to closely attached. Lobes linear-elongate to shallowly rounded to ± dichotomously branching, thin and rather brittle, imbricate centrally, apices discrete, margins entire at apices or ± bifurcate, highly dissected in older parts, isidiate, often ± subcanaliculate, margins ± thickened. Upper surface dark leaden grey to bluish-black when wet, pale lilac-brown to grey-brown when dry, smooth, shining, not tomentose, without soredia, maculae or pseudocyphellae. Isidia mainly marginal, occasionally laminal, flattened, or terete, not tomentose, concolorous with thallus. Medulla white. Photobiont blue-green. Lower surface pale buff or white at margins, darker brown to ochre centrally, glabrous, slightly wrinkled at margins, tomentose centrally, glabrous in a narrow marginal zone, elsewhere tomentose, tomentum to margins in older lobes, short, regular, whitish, silky. Pseudocyphellae white, minute, fleck-like, 0.1-0.6 mm wide, rarely to 1 mm wide, rather sparse, flat, sunk in tomentum. Apothecia submarginal to scattered, 1.5-3.0 mm diam., disc red-brown, margins pale whitish, irregularly dentate-lacerate or crenulate, thalline exciple pale, corrugate-verrucose. Ascospores brown, oblong-fusiform, 1-3-septate, 24-42 × 8-11 µm. Chemistry: 7β-acetoxy-hopan-22-ol, hopane-15α,22-diol, ± gyrophoric acid.
N: S: St: Throughout, lowland, coastal and inland in low-light habitats. Common in deep shade on tree trunks and on rocks on the forest floor in lowland forest, especially in North I.
Australasian
Considerable variation is shown in the abundance and morphology of isidia. P. dissimilis is a fragile, brittle species when dry and like P. cinnamomea to which it is closely related (it is distinguished by the presence of isidia and the lack of a darkened, costate midrib on the lower surface) stains herbarium paper reddish-brown on storage. It is the most common species of the genus in low-light habitats and in many dense North I., forests is the only species commonly met with. Some forms with sparse marginal isidia are difficult to distinguish from P. cinnamomea. It is distinguished from P. fimbriatoides by the glabrous isidia which are never tomentose:
