Usnea pusilla (Räsänen) Räsänen
U. florida var. pusilla Räsänen, Revta Univ. Santiago 21: 139 (1936).
Thallus rather delicate, shrubby, ± fruticose or decumbent-straggling, 1-2.5 (rarely to 4) cm long, blackened at base, pale greenish-yellow, sparsely branched, 1-3-branched at base. Branches 1 mm thick at base tapering towards apices, terete, distinctly papillate, articulate-cracked, fibrils or secondary branches at right angles to main, inflated primary branches sparse to moderate, occasionally dense, matt or shining, waxy, lacking isidia, pseudocyphellae, soredia or spinules. Apothecia moderate to frequent, subterminal, geniculate, disc concave to plane, 1.5-2 mm wide, disc white-pruinose, margins with ray-like branchlets, exciple smooth, matt or slightly faveolate-wrinkled. Ascospores 9 × 5-6 µm. Chemistry: Usnic acid.
N: Northland to Wellington. S: Nelson to Southland. A common and often conspicuous epiphyte of Discaria and Leptospermum, and Dracophyllum at treeline, lowland to subalpine.
Austral
The most constantly fertile, small, delicate, species of Usnea in New Zealand. A related South American species U. simplex Mot., is recorded from Broken River [Motyka loc. cit., p. 582] but confirmation of this observation remains to be tested.
A similar consistently fertile entity containing stictic acid in the medulla is known from Discaria and Dracophyllum from several localities in Canterbury (Cass, Cave Stream, Porters Pass) and may possibly be an undescribed species. It has very densely papillate branches and the apothecial exciple is papillate-scabrid rather than smooth as in U. pusilla.
