Flora of New Zealand Series

Holotype: New Zealand. Canterbury, Mt Misery, Cass, upper subalpine belt. G. Einar and Greta Du Rietz 1468: 16, 1927, S.

Thallus determinate, effigurate, orbicular to irregularly spreading, to 6 cm diam., saxicolous. Marginal lobes swollen, expanded at apices, rounded, crenate, discrete or becoming confluent, usually separated by narrow cracks, extending into centre of thallus, lobes also transversely cracked, wrinkled or folded. Upper surface distinctly rust-red to orange-brown, epruinose, areolate centrally, areolae swollen, rounded to irregular, 0.5-2 mm diam., isidia absent, sorediate. Soredia sparse to numerous, grey-white, erumpent, subrotund, to 2 mm diam., forming abraded patches on areolae. Cephalodia sparse, rounded to irregular, or radially lobate, 2-5 mm diam., brownish-red, dull, epruinose. Apothecia not seen. Pycnidia immersed in areolae, ostiole minute, punctiform. Conidia filiform, straight or curved 13-16 × 0.5 µm. Chemistry: Cortex K-, C+ red; medulla K-, C+ red, KC+ red, Pd+ red.

N: Tongariro National Park, Kaimanawa Ra., Tararua Ra. S: Nelson (St Arnaud Ra., Mt Technical), Canterbury (Arthur's Pass, Mt Misery, Cass, Ben Ohau Ra., Mt Peel, Kirkliston Ra.).

Endemic

P. lateritioides is found most commonly on rocks and stones in alpine or subalpine regions east of the Main Divide. It tolerates a lower rainfall than many other species in the genus and is characterised by the orange-rust thallus with greyish soredia.