Pyxine consocians
Pyxine consocians is a species of foliose lichen in the family Caliciaceae. It was first described from the Philippines, growing on tree bark, and has since been found widely across Asia and the Pacific, including India, South Korea, Sri Lanka, Thailand, and the Gilbert Islands. The lichen forms a thin, leaf-like thallus with a bluish-grey upper surface and produces small black fruiting bodies. Chemical studies have identified several compounds in the lichen, including atranorin, zeorin, and lichexanthone.
Taxonomy
Pyxine consocians was first described by the Finnish lichenologist Edvard August Vainio in 1913. Vainio considered it closest to Pyxine glaucescens, differing by its more granular thallus and by the reaction of the ; in these it agrees with Pyxine retirugella, which in turn differs from P. consocians in the colour and chemical reaction of the thallus.Description
Pyxine consocians is a foliose lichen. The is fairly thin, bluish-grey above and epruinose, somewhat opaque, and lacks soredia and isidia. Its surface is faintly net-like and wrinkled, and the medulla is white. In basic chemical tests, the upper surface gives no reaction, while the inner medulla reacts K+. The are irregular, 0.5–1 mm wide, closely adjoining or merging together, flat, and have slightly roughened or grainy margins. The underside is dark and bears short, black, inconspicuous rhizines that attach it to the substrate.The are 0.5–1.6 mm across and in form, with a blackish to ashy-black rim. The is flat, black, and uncoated, and the inner is pale whitish. The is whitish below, brownish above, and K−, while the is greenish to sooty and K+. Ascospores, which number eight per ascus, are arranged in two rows, brownish, to oblong with rounded ends, and divided by a single septum. Their walls are unevenly thickened, and they measure about 20 μm × 6 μm. Korean specimens showed more crowded, irregularly branched lobes with blunt tips, a greyish-yellow upper surface, and a black lower surface bearing coarse rhizines tipped with pale ends.
Pyxine consocians has been reported to contain several secondary metabolites: atranorin, methyl-β-orcinolcarboxylate, zeorin, 4-O-methylcryptochlorophaeic acid, lichexanthone, and cabraleadiol monoacetate, a triterpenoid compound. More recent studies have also detected norstictic acid, and noted that the thallus reacts K+ and the medulla K+, C+, and P+.