Flora of New Zealand Series

=?Usnea arida Motyka, Lich. Gen. Usnea 2: 492 (1937).

Description : Flora (1985: 598 – as Usnea arida). See also Herrera-Campos et al. (2001: 251) and Wright (2004).

Chemistry : Thallus and medulla K+ yellow→red, C−, KC+ red, Pd+ orange; containing salazinic, norstictic, and usnic acids.

N: Northland to Wellington. S: Nelson to Southland. St: Widely distributed, lowland and coastal. Epiphytic on bark of Metrosideros, Leptospermum, Olearia, Weinmannia, fruit trees, dead twigs, stumps, fenceposts, wooden gates and outbuildings. Known also from Great Britain, Europe, Macaronesia, North America, Mexico, India, Japan, Taiwan, Indonesia, Australia and Chile (Herrera-Campos et al. 2001; Clerc 2004; Wright 2004).

Cosmopolitan

Illustrations : Herrera-Campos et al. (2001: 240, fig. 4; 242, fig. 7; 243, fig. 8; 247, fig. 13A; Dobson (2005: 442).

Usnea cornuta is characterised by: the corticolous habit; the compact, shrubby nature of the thallus; a wide medulla (U. fragilescens -group); narrow axis, branches slightly to markedly inflated; numerous, punctate soralia that may become in part isidiose and confluent; and salazinic and norstictic acids in the medulla (K+ yellow→red). It is discussed by Herrera-Campos et al. (2001), Wright (2004) and Clerc (2004: 80).