Placopsis rhodophthalma (Müll.Arg.) Räsänen
Lecanora rhodophthalma Müll. Arg., Flora 62: 164 (1879).
L. tararuana Zahlbr., Denkschr. Akad. Wiss. Wien math.-naturwiss. Kl. 104: 348 (1941).
Holotype: New Zealand. Westland, ex Herb. F. v. Mueller, 1879, G.
Thallus subdeterminate or effuse, sometimes effigurate at periphery with poorly-defined lobes to 1.5 mm long, saxicolous and terricolous. Upper surface continuous or sparingly cracked, never areolate, slightly wrinkled or warted-uneven, more rarely smooth, whitish, glaucous-white, creamish or with a purplish or rosy tinge, without isidia or soredia. Cephalodia scattered, sessile, irregular to ± orbicular, flattened, to 1.5 mm diam., wrinkled or radially folded, effigurate, pale yellowish or flesh-coloured, matt. Apothecia irregularly scattered, subpedicellate, orbicular, to 2.5 mm diam., thalline margins thick, entire, matt, epruinose, proper margin finally developed, slightly prominent, entire, pink or pale brown, disc plane to subconvex, smooth, rose-red, pinkish or red-brown, matt, glabrous or white-pruinose. Hymenium 210-310 µm tall, nubilated in upper parts. Hypothecium colourless. Ascospores uniseriate, broadly ellipsoid, 20-27 × 9-18 µm. Pycnidia rarely seen. Chemistry: Cortex K-, C+ red; medulla K- or brownish, C+ red, Pd-.
N: Taranaki (Mt Egmont), Wellington. S: Nelson to Fiordland. St: On rocks and soil, coastal to subalpine, common in high rainfall areas on gravels and soil in riverbeds and glacial moraines.
Austral
P. rhodophthalma is closely related to P. parellina but is distinguished by the lack of soredia, the higher hymenium and larger, often very broadly ellipsoid spores.
