Usnea inermis
Description : Flora (1985: 599).
Chemistry : Thallus K+ deep yellow; containing usnic, psoromic, and conpsoromic acids.
N: Northland (Warawara Ra., Kawerua, Bay of Islands, Aorangi I., Hen & Chickens Is, Great Barrier I., Little Barrier I.), Auckland (Auckland City), South Auckland (Mt Maungatawhiri Coromandel Peninsula, Great Mercury I., Slipper I., Whale I., Rotorua, Hamilton), Wellington (Kapiti I., Mokopuna I.). S: Marlborough (d'Urville I.), Canterbury (Riccarton Bush, Prices Valley, Mt Sinclair Banks Peninsula), Otago (Omarama, Shag Valley, Waikouaiti River, Flagstaff, Wairongoa, Waipori, Maungatua), Southland (the Wilderness, Borland Bog). St: (Islet Cove, Port Pegasus). Coastal and lowland to subalpine on scrub. On trees and shrubs in coastal forest; frequent on introduced trees and shrubs and on decorticated wood (fenceposts, gates etc.). Known also from Australia (Stevens 1999, 2004b; McCarthy 2003c, 2006).
Australasian
Illustrations : Walker (1985: 118, fig. 37); Stevens (1999: 15, fig. 4C; 55, fig. 28); Flora of Australia56A (2004: 100, pl. 31).
Usnea inermis is characterised by: the corticolous habit; the tufted to somewhat caespitose, yellow-green thallus that is sometimes with black banding or even completely superficially blackened; irregularly to densely branched; terete to angular-compressed branches, 1–1.5 mm wide at base, with long secondary branchlets parallel to primary branches; pseudocyphellae sparse to frequent, becoming eroded-pulverulent and developing farinose, yellowish green to blackened soredia; and with psoromic acid (K+ yellow) as a major secondary compound. Subalpine collections from Discaria and Melicytus alpinus are often superficially blackened and strongly resemble species of sect. Neuropogon; however, the presence of psoromic acid (K+ deep-yellow) and the corticolous habit distinguishes U. inermis from U. acromelana.
