Flora of New Zealand Series

≡Sporopodium caucasicum Elenkin & Woron., Jber. Pflanzen-Krankh. St . Petersburg 2: 124 (1908).

≡Calenia caucasica (Elenkin & Woron.) Vězda, Scheda Lich. sel. Exsicc. No. 1512 (1978).

Description : Thallus crustose, epiphyllous, whitish grey, smooth, ecorticate, 1–3 mm diam., with scattered stout bristles and a narrow white or hyaline prothallus. Hyphophores rare, 0.4 mm tall and 0.2 mm diam., whitish to hyaline. Apothecia 2–5 per thallus, sunk in the thallus, 0.1–0.3 mm diam, disc pale yellowish grey, greenish grey or grey, epruinose, plane to subconcave. Epithecium incorporating numerous algal cells, smaller than main photobiont. Hymenium hyaline, 40–70 μm tall. Paraphyses 1.5 μm thick, somewhat branched and anastomosing, densely septate. Asci broadly clavate to oblong. Ascospores muriform, 50–70–90 × 12–15 μm.

S: Nelson (Pakawau Creek Road, Golden Bay), Marlborough (Pelorus Bridge). Foliicolous, on leaves of Beilschmiedia tawa, Coprosma grandiflora, Griselinia littoralis, Pittosporum tenuifolium, Podocarpus totara, Schefflera digitata in lowland mixed podocarp– Nothofagus forest (Malcolm & Vezda 1997a). Known also from Asia, Japan, East Africa, Central America, Brazil, Argentina, Papua New Guinea, New Caledonia, and Australia (Ferraro et al. 2001; Lücking & Kalb 2001; McCarthy 2003c, 2006; Lücking et al. 2003; Nimis & Martellos 2003).

Pantropical

Illustrations : Vězda (1979: 84, pl. 2, fig. 8 – as Calenia caucasica); Sérusiaux & De Sloover (1986: 286, figs 24–27); Lücking (1992: 106, fig. 38B); Lumbsch et al. (2001a: 46); Malcolm & Malcolm (2001: 35, 49 – as Gyalectidium cf. palmicola).

Gyalectidium caucasicum is characterised by: the foliicolous habit; the minute white, smooth thallus, 1–3 mm diam.; occasional to rare, whitish hyphophores present, 0.4 × 0.2 mm; the minute, aggregated, minute semi-immersed apothecia with greyish or whitish discs; algal cells in the epithecium; monosporous asci; and colourless, muriform, smooth-walled ascospores. It is commonly overlooked because of its minute thallus. Macolm & Vězda (1997a) note a number of differences between the New Zealand specimens and European collections of G. caucasicum  s. str., viz.: NZ specimens differ in having a distinctly lobulate thallus (the thallus of G. caucasicum is ±rounded) and a differing chemistry, having traces of usnic acid and two unidentified compounds (G. caucasicum has no chemistry). Malcolm & Malcolm (2001: 35, 49) use the name G. cf.palmicola Farkas & Vězda New Zealand material, but G. palmicola is a presumed Cuban endemic (Ferraro et al. 2001: 341), and besides, the New Zealand material has ascospores that are longer than both G. palmicola (30–45 × 10–15 μm) and G. caucasicum (40–50 × 10–15 μm). G. caucasicum admittedly has a much wider geographical distribution than C. palmicola, so the possibility exists that the Nelson material is an independent taxon.