Flora of New Zealand Series

≡Thysanothecium buchanani C.Knight, Trans. N. Z. Inst. 13: 386 (1881).

=Phloeopannaria athrophylla, sensu Zahlbr., Denkschr. Akad. Wiss. Wien math.-naturwiss. Kl. 104: 276 (1941).

Lectotype: New Zealand. Otago, "Supra molem nivium frigoribus conglaciatum in summis montibus ('Aspiring Range') alt 400 peds". J. Buchanan – H-NYL 30797 [fide Galloway (1985a: 470)]; isolectotype – WELT.

Description : Flora (1985: 470).

Chemistry : TLC−, all reactions negative.

S: Nelson (Mt Arthur summit, St Arnaud Ra., Crimea Ra.), Marlborough (Mt Tapuaenuku, Inland Kaikoura Ra., Carter's Saddle, Clarence Valley), Canterbury (Craigieburn Ra., Foggy Peak Torlesse Ra., Black Hills Rakaia Valley, Mt Dobson, Upper Godley Valley, Cass River, Two Thumb Ra., St Marys Ra.), Otago (Lake Ohau, Mt Aspiring, Mt Joffre, Barrier Ra., Bride Burn, Fohn Saddle, North Col, Ocean Pk, Humboldt Mts, Bedford Valley, Pisa Ra., Coronet Peak, Old Man Ra., Poolburn Reservoir, Lake Onslow, Kakanui Mts, above Benmore Dam, Rock & Pillar Ra.). A characteristic scree and fellfield species growing on soil in alpine grassland, or among mosses in alpine to high-alpine habitats mostly E of the Main Divide, 800–3000 m. Commonly associating with Coccocarpia palmicola, Massalongia carnosa, Parmelia signifera and Toninia bullata in drainage cracks on rock faces, or in soil-filled fissures in rocks. Known also from the South Orkney Is, the South Shetland Is, and James Ross I. (Søchting et al. 2004: 647).

Austral

Illustrations : Knight 1881 (pl. XVII, figs 1–4 – as Thysanothecium buchanani).

[It is likely that the Aspiring Ra. referred to by Knight and Buchanan is Mt Alta and/or the Buchanan Peaks, on the true left of the Matukituki River, well down the valley and overlooking Lake Wanaka, and not Mt Aspiring itself. Although John Buchanan first visited the Matukituki Valley with James Hector in 1862, the bulk of his botanical collections for that region were made on Mt Alta in 1881 with James Park and Alexander Mackay (Adams 2002).]

Psoroma buchananii is characterised by: the terricolous habit; the thickly spreading, concrescent, yellow-brown to dark red-brown or grey-black thallus of swollen, hummocky squamules; occasional to frequent, sessile to subpedicellate apothecia, 1–10 mm diam., with a matt, red-brown, shallowly to deeply convex disc and a conspicuous crenate-striate to verrucose-areolate thalline exciple; and variable, spherical to ellipsoidal ascospores, 15–22 × 10–15 μm. In his account of Phloeopannaria athrophylla, Zahlbruckner (1941: 276) gives a good description of Psoroma buchananii (Zahlbruckner's name referring to the bark-like colour and surface texture of P. buchananii), mistakenly synonymising it with Pannaria athroophylla (q.v.) and also misspelling Stirton's epithet (see above) In his description of Phloeopannaria (Zahlbruckner 1941: 275), he gives as the main characters separating his genus from Pannaria the chondroid upper cortex composed of thickly gelatinised and conglutinated vertical hyphae, and Nostoc as photobiont.