Usnea trichodeoides
Description : Thallus pendulous, to 100 cm long, pale-green or yellow-green, rarely deep grey-green, pale at base, branching subdichotomous. Branches terete, 0.5–1 mm diam., slender to here and there broadened, flattened and ribbon-like, with numerous annular cracks; secondary branches parallel; without branchlets; fibrils many, smooth or cracked, to 2 mm long, sometimes with pseudocyphellae. Without isidia, papillae or soredia. Cortex dull, partly eroding along branches. Medulla dense, narrow; axis ¾ width of branch, hyaline. Apothecia not seen.
Chemistry : Thallus K+ brownish; containing protocetraric and usnic acids.
N: South Auckland (Whale I.). On coastal shrubs. Known also from NE Australia, Norfolk I., Africa, Madagascar, Réunion, Asia, and Japan (Swinscow & Krog 1978b, 1988; Stevens 1999, 2004b; Ohmura 2001).
Palaeotropical
Illustrations : Swinscow & Krog (1978b: 240, fig. 27); Stevens (1999: 14, fig. 3C; 17, fig. 5C); Ohmura (2001: 7, fig. 4C; 15, fig. 13B); Flora of Australia56A (2004: 102, pl. 37).
Usnea trichodeoides is characterised by: the corticolous habit; the long pendulous branches, terete to flattened and ribbon-like; the partly eroded cortex; the relatively thick axis; and protocetraric acid in the medulla.
