PSEUDEPHEBE ¹

Gintaras Kantvilas ²

Pseudephebe M.Choisy, Icon. Lich. Univ., ser. 2, fasc. 1 (unpaginated) (1930).

Type: P. pubescens (L.) M.Choisy

Thallus fruticose, prostrate, mostly dark brown to blackish, erhizinate, attached to the substratum by scattered, disc-like hapters; branches terete or unevenly dorsiventrally flattened, lacking cilia, maculae, pseudocyphellae, soredia and isidia; cortex N–, composed of short, periclinal hyphae; medulla lax, lacking a chondroid axis. Photobiont trebouxioid. Ascomata apothecia, lecanorine, lateral; proper exciple cupulate; thalline exciple often becoming excluded. Asci 8-spored, of the Lecanora-type: broadly clavate, with a well-developed, amyloid tholus, pierced entirely by a non-amyloid masse axiale with ± parallel flanks; ocular chamber poorly developed. Paraphyses rather stout, straight, sparsely branched; apices not expanded. Ascospores simple, hyaline, broadly ellipsoid. Conidiomata pycnidia, laminal, immersed; conidia bacilliform. Chemistry: nil.

A bipolar genus comprising two species, widely distributed on rocks in cold, montane or polar environments. One species occurs in Tasmania.

Key references: Brodo & Hawksworth (1977); Kantvilas (1994); Kantvilas et al. (2002).

1 Pseudephebe pubescens (L.) M.Choisy

Icon. Lich. Univ., ser. 2, fasc. 1 (unpaginated) (1930); —Lichen pubescens L., Sp. Pl. 2: 1155 (1753); Alectoria pubescens (L.) R.Howe, Classif. Usneac. Amer.: 23 (1912).

Thallus dark olive-brown to blackish, glossy, paler in shaded parts, forming straggling, wiry, tightly adnate mats to 10 mm high and 120 mm across; branches terete (often rather unevenly so), much-branched and entangled, to c. 0.4 mm thick. Apothecia unknown in Tasmania, reported as to 5.5 mm wide, with ascospores 7–12 × 6–8 µm (Brodo & Hawksworth 1977).

A bipolar species with a widespread Tasmanian distribution. Virtually all collections are from dolerite peaks, but this is more likely a reflection of the generally higher elevation and greater availability of habitat on these mountains, rather than a preference for a particular rock type. Pseudephebe pubescens forms wiry mats and tufts on the apices of large, exposed, alpine boulders, where it is usually part of a diverse lichen association that includes Notoparmelia signifera, Usnea torulosa, Xanthoparmelia stygiodes and species of Umbilicaria. It is very distinctive and unlikely to be mistaken for other lichens. Blackened species of Usnea and Neuropogon, which can occur in the same habitats, are inevitably more robust, retain some hint of yellow coloration and have a central chondroid axis. Although there is a superficial resemblance to the genus Ephebe, that lichen has finer branches, occurs in semi-aquatic or very wet habitats, and contains a cyanobacterial photobiont.

Mt Wellington, 1963, P.W. James s.n. (BM, HO); Sandbanks Tier, 41°50’S 146°51’E, 1969, G.C. Bratt 69/206 (HO); western flanks of Legges Tor, 41°32’S 147°39’E, 1530 m, 1998, G. Kantvilas 107/98 (HO).

References