Thelotrema obovatum Stirt.
Lectotype: New Zealand. Near Wellington (Tinakori Hills). J. Buchanan 57b, GLAM!
Thallus pale yellowish-buff or pale olivaceous, matt, or minutely granular or lumpy-warted, continuous to ± areolate-cracked, c. 100-150 µm thick. Apothecia frequent, sessile, 0.2-1.0 mm diam., in conspicuous thalline warts, hemispherical, constricted at base, pore 0.1-0.5 mm diam., margins swollen, entire, not fissured, concolorous with thallus, disc white. Exciple detached, colourless or pale brownish, c. 30-35 µm thick. Hymenium colourless, 100-120 µm thick. Ascospores 8 per ascus, 15-20-locular, oblong-fusiform with pointed ends, or one end obtuse the other attenuate-acute, (36-)60-80 × (8.3-)9-14 µm, spiral in ascus. Chemistry: Nil.
N: Wellington. S: Otago (Mt Maungatua). On bark of forest trees, s.l. to 1000 m.
Endemic
Salisbury [ Lichenologist 5: 265 (1972)] refers T. obovatum to T. porinoides Mont. v.d. Bosch, a species from Java, but there are differences in spore size and septation which seem to argue for retention of Stirton's name for the New Zealand material. In a later paper Salisbury [ Lichenologist 7: 59 (1975)] records T. subdenticulatum (Zahlbr.) Salisbury, from Mt Maungatua near Dunedin (collected by P.W. James in 1962 from Nothofagus bark at 1000 m) but it is probable that the record is more correctly T. obovatum. T. subdenticulatum is a species from Juan Fernandez which closely resembles T. obovatum and the two may be conspecific. If so, and it still remains to be proved, T. obovatum takes priority, since T. subdenticulatum was described only in 1924.
