Flora of New Zealand Series

≡Usnea dasypogoides var. torulosa Müll.Arg., Flora 66: 19 (1883).

=Usnea aurescens Motyka, Lich. Gen. Usnea 2: 561 (1937).

≡Usnea torulosa var. aurescens (Motyka) G.N.Stevens, Biblthca Lichenol. 72: 109 (1999).

Usnea aurescens. Lectotype: New Zealand. Otago, Cave Hill, Dunedin, on rock, J.S. Thomson T245 [M23] – CHR 343970 [fide Galloway (1985a: 603)]. Paratype: Otago, Cave Hill, Fortification Creek, on rock, J.S. Thomson T244 – OTA 02098.

Description : Flora (1985: 603).

Chemistry : Three distinct chemodemes are found in this species, and may in fact represent independent taxa: (1) psoromic, conpsoromic , ±squamatic and usnic acids, (2) squamatic and usnic acids [the type has this chemistry], (3) barbatic, 4- O -demethylbarbatic, squamatic (UV+ white) and usnic acids [the type of U. aurescens has this chemistry].

S: Nelson (Lake Cobb, Kakapo Peak, Mt Arthur, St Arnaud Ra.), Canterbury (Lewis Pass, Arthur's Pass, Cass, Craigieburn Ra., Foggy Peak Torlesse Ra.), Otago (Mt Earnslaw, The Remarkables, Garvie Mts, Pisa Ra., Dunstan Mts, Old Man Ra., Poolburn Reservoir, Rock & Pillar Ra., Horse Ra., Mt Misery, Lamb Hill, Silver Peaks, Waikouaiti Reservoir, Swampy Summit, Flagstaff, Maungatua, Waipori, Blue Mts), Southland (West Dome, Fiordland). Known also from Australia (Stevens 1999, 2004b; McCarthy 2003c, 2006).

Australasian

Illustrations : Walker (1985: 119, figs 38B, C); Stevens (1999: 108, figs 70, 71).

Usnea torulosa is characterised by: the saxicolous habit: the erect or subdecumbent thallus to 5 cm tall, greenish yellow, pale-yellow or yellow-white, blackened at base; the simple, straight branches, 1–1.5 mm diam.; the glossy, waxy, annulate-cracked cortex; round to irregular, punctate to spreading pseudocyphellae that become granular-sorediate; and a variable secondary chemistry, generally containing squamatic acid (UV+ white).