Peltularia crassa P.M.Jørg. & D.J.Galloway
Holotype: New Zealand. Campbell Island, just below the summit of Mt Lyall. On stones in fellfield scree, 365 m. 20 January, 1981. C.D. Meurk, BM!
Thallus foliose, monophyllous, appearing umbilicate, attached to substrate by several disc-like holdfasts, saxicolous. Lobes to 1.5 cm diam., margins slightly incised or crenulate, often coarsely sorediate. Upper surface matt, or ± scabrid, greyish-brown, with rounded, maniciform, coarse-grained bluish soralia. Lower surface pale pinkish-white, verrucose, often ± faveolate-lacunose, occasionally with coarse, bluish soralia. Apothecia very rare, to 1 mm diam., erupting through upper cortex, pushing forward a thalline margin concolorous with thallus, sometimes heavily sorediate, disc plane, matt, brown. Hymenium (90-)100-120 µm tall, upper part pale brown, I+ deep blue. Paraphyses simple, rarely bifurcating at apices, 2 µm thick, slightly expanded at apices with brownish pigment externally. Asci broadly clavate, (70-)75-80(-85) × 20-25 µm, tapering towards base, thick-walled especially at apex, with an external amyloid cap. Ascospores 8 per ascus, colourless, thin-walled, (2-)3-septate, (15-)20-25 × 7-8 µm. Chemistry: TLC nil.
C: M: On rocks in exposed fellfield and scree. Associating with: Cladia aggregata, Hypogymnia lugubris, Placopsis subgelida, Pseudocyphellaria delisea, Steinera sorediata and Usnea xanthopoga.
Endemic
P. crassa is a distinctive lichen characterised by the foliose, ± umbilicate thallus, blue-green photobiont and the laminal soralia. It is one of a group of relict lichen genera (Argopsis, Knightiella, Steinera are others) developed in the subantarctic, which should be closely looked for in the mountainous areas of southern New Zealand.
