Usnea simplex
Description : Thallus erect, small, to 2.5 cm tall, greenish or yellow-green, dichotomously branched. Branches terete, 0.5–0.8 mm diam., simple, or 1–2-branched at base, apices attenuate, cortex continuous or rarely transversely cracked, indistinctly papillate. Branchlets crowded to regularly spaced along branches, pale, smooth, subinflated, frequently transversely cracked. Medulla lax; axis ¼–⅓ width of branch, hyaline. Apothecia subterminal, to 3 mm diam., plane to subconvex. Exciple smooth, glossy, concolorous with thallus, wrinkled-faveolate with age. Cilia projecting from margins, short, pellucid, commonly cracked. Ascospores 18 × 8 μm.
Chemistry : Medulla K−; containing usnic acid.
S: Canterbury (Broken River). On subalpine shrubs. Known also from southern Chile (Motyka 1938; Herre 1960; Galloway & Quilhot 1999).
Austral
Usnea simplex is characterised by: the corticolous habit; the small thallus; and simple, rarely divided branches that are only indistinctly papillate. Usnea pusilla (q.v.) is similar, but has more robust branches that are distinctly papillate.
