Siphula dissoluta Nyl.
S. roccelliformis Nyl., Lich. N.Z.: 15 (1888).
Lectotype: New Zealand. Westland, Greymouth. Richard Helms 131, 1886, H-NYL!
S. roccelliformis. Lectotype: New Zealand. Canterbury. Sinclair and Haast, BM!.
Thallus lobes coarse, 3-8 mm wide and 5-20 mm tall, distinctly unilaterally thickened at apices, apices rounded, undulate, margins entire or slightly incised, ± wavy. Surface coarsely scabrid, areolate or corrugate, white, in low-light or sites of high humidity lobes thinner and often ± fenestrate with lacerate, ragged margins. Chemistry: Medulla K+ violet-purple, Pd-. Hypothamnolic acid (UV+ vivid blue-white).
N: Northland (Great Barrier I., Mt Hobson). Auckland (high peaks of Coromandel Ra., Te Aroha). Wellington (Tararua Ra.). S: Nelson (St Arnaud Ra.) and southwards to Fiordland on mountains on both sides of the Main Divide. St: (Mt Anglem and the Tin Ra.). On soil or amongst moss in exposed alpine habitats, 1000-1200 m.
Endemic
S. dissoluta is a ± common lichen in many exposed alpine habitats; occasionally it is found below treeline on soil at the sides of tracks used by deer or by trampers. North I., collections are mainly from amongst moss in ± humid sites and are ± conspicuously fenestrate. However, these seem merely morphological variants induced by high humidity and low-light, in analogous fashion to the variation in morphology induced by differing ecological conditions seen also in S. decumbens.
