Flora of New Zealand Series

R. allanii B. de Lesd., Bull. Soc. bot. fr. 84: 283 (1937).

Thallus erect to pendulous, to 12 cm rarely to 20 cm long, corticolous. Branches rigid, yellowish-green to greyish, angular-terete to slightly flattened, longitudinally striate-nervose, exposing white medulla, or cracked, shortly branched, narrow, 1.5 mm wide at base tapering to 0.5 mm wide at apices, lateral branches narrower, numerous, irregularly divided, subterete, apices finely flexed or bent, without pseudocyphellae or soredia, longitudinally ridged or grooved near base. Apothecia rare, lateral, sessile, plane, 0.9 mm diam., disc pale yellowish-pink, epruinose, margins thin, entire, concolorous with thallus, thalline exciple smooth. Ascospores oblong, 12-15 × 4-6 µm. Chemistry: No medullary substances.

N: Northland to Auckland including offshore island groups.

Australasian

R. myrioclada is a pendulous, narrow-branched, Usnea -like species occurring as an epiphyte of Leptospermum, Avicennia and Metrosideros in northern coastal forest. It is distinguished from R. arabum in the thicker and less terete branches and the lack of medullary substances. In early accounts of New Zealand lichens this species was referred to as R. usneoides. Forster's specimen (UPS-THUNBERG 26348) from New Zealand and named by Acharius Usnea cornicularia [ Lich. Univ.: 619 (1810)] is probably referable to this species, in which case Acharius's epithet should have priority.