Krogia microphylla Timdal
Mycobank MB 517788
Thallus squamulose, effuse. Squamules to 0.3 mm wide when young but soon coalescing into a continuous, microphyllinous crust, deeply and irregularly divided into ca. 0.1 wide lobes, ascending, irregularly imbricate, pale brown (old herbarium material), with scattered patches of orange (K+ purple) spots, epruinose, dull; margin concolorous with upper side, not fibrillose; lower side pale brown; soredia and isidia absent. Upper cortex poorly defined, composed of a thin, rather loose layer of irregularly oriented hyphae. Algal layer filling the inner part of the squamule. Medulla and/or lower cortex poorly defined. No crystals in thallus section (polarized light), PD–, K–, K/I–. Prothallus lacking. Apothecia biatorine, to 0.7 mm diam. when simple, but often forming up to 1 mm diam. aggregates, with a rusty brown, more or less plane disc and a grayish brown, slightly shiny, not fibrillose, often flexuous margin. Proper exciple dark olivaceous brown, K+ green in the inner part, pale brown to colourless in the rim, composed of radiating, closely conglutinated, thick-walled hyphae with cylindrical lumina, not containing crystals. Hypothecium continuous with proper exciple, dark olivaceous brown, K+ green, composed of closely conglutinated, thick-walled hyphae with angular to cylindrical lumina, not containing crystals. Hymenium and epithecium colourless, not containing crystals. Paraphyses simple or sparingly branched, moderately conglutinated, rather thin-walled; apical cell slightly swollen, colourless. Ascus clavate, surrounded by a thin amyloid sheet; tholus well-developed, not amyloid or with a wide, faintly amyloid tube, with a well-developed ocular chamber when young. Ascospores eight in the ascus, colourless, thin-walled, filiform, curved, spirally arranged, simple or with 1–3 pseudosepta, 25–35 x ca. 1.0 µm (n = 20). Secondary chemistry: no lichen substances (by TLC).
The genus Krogia and its originally sole species, K. coralloides Timdal, was described from one locality in Mauritius (Timdal, 2002). A second species, K. antillarum Timdal, was described from six localities in the West Indies (Timdal, 2008), and a third species is described here. Krogia is a corticolous genus occurring in subtropical rainforests and closely resembling Phyllopsora. It differs from Phyllopsora in having a weak or absent amyloid reaction in the tholus and filiform, curved ascospores which are spirally arranged in the ascus. The new species differs from Krogia coralloides and K. antillarum in forming smaller squamules which do not contain secondary substances, in having rusty brown apothecia with a grayish brown margin, and in having a dark olivaceous brown, K+ green hypothecium and inner part of the proper exciple. Krogia coralloides forms up to 1 mm wide squamules and contains boninic acid (Timdal, 2002), and K. antillarum forms up to 1.5 mm wide squamules and contains 4-O-methylcryptochlorophaeic acid (Timdal, 2008); both species have medium brown apothecia with a margin concolorous with or slightly paler than the disc, and a pale-brown, K– hypothecium and inner part of the proper exciple. The ascus and ascospores of K. microphylla are indistinguishable from those of the two other species.
The species is named after the tiny squamules.
Krogia microphylla is known only from the holotype. The collecting site was, according to the label, cloud forest in ravine and scattered trees in pasture at ca. 450 m altitude. Two species of Phyllopsora were collected at the same site: P. chodatinica Elix (Harris 26683, NY) and P. furfuracea (Pers.) Zahlbr. (Harris 26725, NY).
Type:—DOMINICAN REPUBLIC: El Ceibo: 25 km N of El Ceibo on road to Miches, 18 km S of Miches; 18°55’N, 69°09’W; Jan 1991, Harris 26749 (holotype NY).
Additional specimens examined (paratypes):—None.
Krogiae coralloidi et K. antillari affinis, sed squamis minoribus, hypothecio obscure olivaceo et thallo acidis lichenosis destituto.