Six new species of the lichen genus Pyrenula (Pyrenulaceae) from Northeast Brazil

摘要

Six new Pyrenula species are described as new to science, viz. Pyrenula aurantiothallina C. O. Mendonca, Aptroot & M. Caceres, with orange thallus with KOH+ purple anthraquinone, simple low conical ascomata, inspersed hamathecium, and ascospores 3-septate, 19.5-22.5 x 7-8.5 mu m, generally somewhat constricted at the septa; Pyrenula coccinea C. O. Mendonca, Aptroot & M. Caceres, with yellowish brown thallus and ascomata with 6 to 25 together immersed in a pseudostromata with partly fused outer walls but separate, apical ostioles, covered with red pruina, ascospores 3-septate, 15-18(-20) x 5-6 mu m; Pyrenula diamantinensis C. O. Mendonca, Aptroot & M. Caceres, with thallus yellowish brown, corticate, partly with a layer of whitish pruina, with (often eroded) pseudocyphellae, ascomata flattened to subglobose, numerous, partly covered by a layer of whitish pruina, 0.3-0.5 mm diam., mostly with 2-10 sideways touching but not totally fused, clypeus in upper half much thicker than below, ascospores 3-septate, 26-33 x 11-16 mu m, lumina mostly obliquely quadrangular; Pyrenula lilacina C. O. Mendonca, Aptroot & M. Caceres, with lilac thallus, simple ascomata, and ascospores 3-septate, 31-37 x 11-14 mu m; Pyrenula supralaetior C. O. Mendonca, Aptroot & M. Caceres, which is similar to P. laetior Mull. Arg., but with ascospores 25-31 x 11-13 mu m; and Pyrenula violaceastroidea C. O. Mendonca, Aptroot & M. Caceres, with ascomata pyriform, aggregated by 3-6 perithecia with a shared ostiole but without joint walls (parmentarioid), ostiole, ascomata and thallus partly covered by wine-red to purplish, KOH+ purple, anthraquinone. They were all found by the first author during several recent field trips in the North and Northeast of Brazil.