LECANOGRAPHA ¹

Gintaras Kantvilas ²

Lecanographa Egea & Torrente, Biblioth. Lichenol. 54: 116 (1994).

Type: L. lyncea (Sm.) Egea & Torrente

Thallus crustose, ecorticate, commonly with a thick, cretaceous medulla, sometimes containing calcium oxalate, lacking a prothallus. Photobiont trentepohlioid, with cells suglobose, 8–15 µm wide. Ascomata apothecia, rounded to elongate, lecideine, immersed, adnate or basally constricted. Disc brown to black, invariably with white, grey or yellowish pruina. Proper exciple prominent and persistent, entire, in section cupulate, opaque black-brown, carbonised, K± greenish, composed of highly gelatinised, amorphous hyphae and remaining opaque with the addition of K. Hypothecium pale to dark brown. Hymenium hyaline, not inspersed, hemiamyloid, KI+ pale blue, overlain by a grey to brownish, crystalline, epithecial layer. Asci cylindrical, 8-spored, of the grumulosa-type: walls and tholus non-amyloid except for a highly reduced, weakly amyloid ring. Paraphysoids richly branched and anastomosed, slender, remaining conglutinated in water and K; apices not swollen. Ascospores transversely 3–12-septate, hyaline when young, often turning brownish with age, oblong-ovoid to fusiform, usually thinly halonate at least when young; locules cylindrical. Conidiomata pycnidia, immersed. Conidia straight or curved. Chemistry: depsides, especially gyrophoric or confluentic acids, or depsidones (psoromic acid) occur in many species, sometimes with additional pigments.

A genus of about 25–30 species, widespread and represented in most regions of the world on rocks, bark or wood. Two superficially similar species are known from Australia, one of which is endemic to Tasmania. The genus appears to be most closely related to Angiactis, with which it shares grumulosa-type asci, slender, branched and anastomosed paraphysoids, and ellipsoid to fusiform, thinly halonate ascospores. Angiactis differs chiefly by having apothecia with a thalline margin and excipular tissues that do not react K+ greenish.

Key references: Egea & Torrente (1994); Kantvilas (2004).

1 Lecanographa nothofagi Kantvilas

Symb. Bot. Upsal. 34(1): 199 (2004). Type: Tasmania, 3 km SW of Mt Agnew, 41°55’S 145°11.5’E, 190 m, on dry trunk of mature Nothofagus cunninghamii in rainforest, 6 April 1989, G. Kantvilas 134/89 (holo—HO!; iso—UPS!).

Thallus finely leprose, whitish, lacking calcium oxalate, forming continuous patches to c. 30 cm wide. Apothecia roundish, 0.3–0.7 mm wide, ± basally constricted or somewhat sunken in the thallus, scattered, typically very numerous; disc plane at first, becoming convex, brown, coarsely white-pruinose; proper exciple black, densely and coarsely white-pruinose and/or covered with thallus fragments, in section 30–50 µm thick laterally, to 160 µm thick basally. Hymenium 60–70 µm thick; epihymenial layer discontinuous, 15–40 µm thick, composed of grey-brown granules that dissolve in K; asci 43–56 × 10–15 µm; paraphysoids rather sparse and indistinct, 0.5–0.7 µm thick. Ascospores fusiform, 5–9-septate, 24–34 × 3–4.5 µm, arranged side-by-side in the ascus, with the halo very thin and ± discontinuous. Pycnidia not found.

Chemistry: confluentic acid, 2’-O-methylmicrophyllinic acid (trace) and 4-O-methylolivetoric acid (trace); thallus K–, KC–, C–, P–, UV–.

Endemic to Tasmania and found mostly on dry, very old trunks of Nothofagus cunninghamii in the rainforests of the west and north-west. One outlying record is from the fibrous trunk of the tree fern, Dicksonia antarctica, in a relict rainforest gully in south-eastern Tasmania. When fertile, this species is easily recognised by the combination of roundish, pruinose apothecia with grumulosa-type asci and multi-septate ascospores. However, sterile thalli (which are not uncommon) can resemble a species of Lepraria and are best identified using TLC.

W of Savage River Pipeline Road, 41°13’S 145°19’E, 450 m, 2003, G. Kantvilas 722/03 (BM, HO); track to Cape Surville, 42°57’S 147°59’E, 110 m, 2000, G. Kantvilas 407/00 (HO).

References