ALECTORIA ¹

Gintaras Kantvilas ²

Alectoria Ach., in Luyken, Tent. Hist. Lich. Gen.: 95 (1809).

Type: A. sarmentosa (Ach.) Ach.

Thallus fruticose, erect or decumbent, yellowish to blackened, often mottled, erhizinate, ± unattached to the substratum; branches terete to subterete, becoming compressed, angular or faveolate near the base and at the axils, lacking cilia or lateral spinules; pseudocyphellae always present; soredia rare; cortex composed of short, periclinal, conglutinated hyphae; medulla lax, lacking a chondroid axis. Photobiont trebouxioid. Ascomata apothecia, lecanorine, lateral; proper exciple cupulate. Asci 2–4-spored, of the Lecanora-type: broadly clavate, with a well-developed, amyloid tholus, pierced entirely by a narrow, non-amyloid masse axiale with ± parallel flanks; ocular chamber poorly developed. Paraphyses rather stout, much-branched and anastomosed; apices not expanded. Ascospores simple, brown, broadly ellipsoid, thick-walled. Conidiomata pycnidia, laminal, immersed; conidia bacilliform. Chemistry: usnic acid (in Alectoria s. str.) and/or depsides.

Alectoria was traditionally a large genus of fruticose lichens found mostly in the Northern Hemisphere, but it has been gradually subdivided into more natural units, including Pseudephebe and several other genera that do not occur in Tasmania (e.g. Bryoria and Oropogon). More recently, on the basis of molecular data, Halonen et al. (2009) further subdivided Alectoria, with the single Tasmanian representative, A. nigricans, transferred to the genus Gowardia. However, with only one, well-known species present in the entire Australasian region, its traditional name in Alectoria is retained here. Gowardia can be recognised macroscopically chiefly by lacking the yellowish, cortical pigment, usnic acid, which is present in Alectoria s.str.

Key references: Brodo & Hawksworth (1977); Kantvilas (1992); Halonen et al. (2009).

1 Alectoria nigricans (Ach.) Nyl.

Lich. Scand.: 71 (1861); —Cornicularia ochroleuca var. nigricans Ach., Lich. Univ.: 615 (1810); Gowardia nigricans (Ach.) Halonen, Myllys, Velmala & Hyvärinen, Bryologist 112: 145 (2009).

Thallus decumbent, straggling over the substratum in extensive mats, intricately branched and entangled, dying at the base, when fresh mostly yellowish and mottled dark bluish grey, especially in the uppermost, exposed parts, becoming pinkish brown with storage; major branches terete to unevenly flattened, 1–1.5 mm wide at the base, tapering to acute apices; pseudocyphellae conspicuous, elongate, fissurine, white, to 0.8 mm long; soredia absent. Apothecia unknown in Tasmania, reported 1.5–4 mm wide, with the ascospores 30–41 × 20–23 µm (Brodo & Hawksworth 1977). Pycnidia not seen.

Chemistry: alectorialic acid; cortex K–, C+ red, KC+ red, P+ yellow, UV–. In storage this substance stains herbarium packets pinkish brown.

A widespread bipolar species, also present on the Australian mainland. It is very localised in Tasmania, growing over small shrubs, peaty soil and rocks in heathland on the highest peaks and plateaux. Significant populations occur on Mawson Plateau and at Cradle Mtn, but elsewhere it is extremely rare. Although superficially resembling a species of Usnea (U. contexta can occupy an identical habitat), Alectoria nigricans is easily distinguished by its finer branches and the absence of a central chondroid axis (seen by pulling the branches when fresh and moist).

Cradle Mtn Plateau near Kitchen Hut, 4000’ [1200 m], 1967, G.C. Bratt 67/595 (Lich. Exsicc. Colo. 241) (HO); 1.5 km W of Chalice Lake, 41°53’S 146°08’E, 1180 m, 1999, G. Kantvilas 93/99 (HO); Mt Mawson Plateau, 42°41’S`146°35’E, 1280 m, 2007, G. Kantvilas 379/07 (HO).

References