PARMELIOPSIS ¹

Gintaras Kantvilas ²

Parmeliopsis (Nyl.) Nyl., Lich. Lapp. Orient.: 121 (1866)

Type: P. ambigua (Wulfen) Nyl.

Thallus foliose, rosette-forming, with lobes elongate and flattened, dorsiventral, plane; upper surface yellow or grey, emaculate, lacking cortical hairs, cilia and pseudocyphellae, corticate, with a pored epicortex; lower surface pale brown to black, with simple rhizines. Photobiont trebouxioid. Ascomata apothecia, lecanorine, laminal, sessile to shortly pedicellate; disc plane to concave, pale brown; proper exciple cupulate. Paraphyses rather stout, straight, simple; apices slightly swollen. Asci 8-spored, of the Lecanora-type: clavate; tholus well-developed, amyloid, pierced entirely by a narrow, non-amyloid masse axiale with parallel flanks; ocular chamber not developed. Ascospores simple, hyaline, ellipsoid to reniform. Conidiomata pycnidia, black, laminal, immersed. Conidia filiform. Chemistry: usnic acid or atranorin in the cortex, with divaricatic acid in the medulla.

A genus of three species found mainly in boreal and temperate parts of the Northern Hemisphere. Its occurrence in the Southern Hemisphere is essentially alpine. Superficially, Parmeliopsis appears very similar to Imshaugia, although DNA data indicate they are not closely related.

1 Parmeliopsis ambigua (Wulfen) Nyl.

Lich. Lapp. Orient.: 121 (1866); —Lichen ambiguus Wulfen in N.J. von Jacquin, Collectanea 4: 239 (1791).

Thallus tightly adnate, pale yellow, to c. 4 cm wide, often with several adjacent thalli fusing into larger colonies; lobes plane or undulate, smooth or weakly rugose in older parts, 0.5–1.5 mm wide, discrete at the apices, crowded and imbricate in the thallus centre, sorediate; lower surface brown to black; soredia farinose, concolorous with the thallus, occurring in laminal, roundish or capitate soralia to 1.2 mm wide that become confluent in the centre of the thallus. Apothecia unknown in Tasmania, reported as to 2 mm diam., with narrowly ellipsoid ascospores, 7–11 × 2.5–3 µm (Ahti et al. 2011). Pycnidia not seen; conidia reported as 12–18 × 0.5–1 µm (Ahti et al. 2011).

Chemistry: usnic, divaricatic and nordivaricatic acids; medulla K–, KC–, C–, P–, UV+ pale bluish.

Widespread on wood and bark, especially in boreal areas; also known from alpine south-eastern Australia. It is very rare in Tasmania (and is listed as such under the Tasmanian Threatened Species Protection Act 1995), having been recorded only once, from the bark of Orites acicularis in alpine heathland at the margins of Athrotaxis cupressoides-dominated woodland.

Walls of Jerusalem, foot of Halls Buttress, 41°49’S 146°18’E, 1330 m, 1987, G. Kantvilas 111/87 (CANB, HO).

2 Parmeliopsis hyperopta (Ach.) Arnold

Verh. K. K. Zool.-Bot. Ges. Wien 30: 117 (1881); —Parmelia hyperopta Ach., Syn. Meth. Lich.: 208 (1814).

Thallus tightly adnate, whitish grey, sometimes discoloured brownish at the periphery, to c. 2 cm wide; lobes plane or undulate, smooth or weakly rugose in older parts, 0.2–0.5 mm wide, discrete and rather spidery at the apices, crowded and imbricate in the thallus centre, sorediate; lower surface black; soredia farinose to granular, whitish or discoloured grey, initially occurring in laminal, roundish soralia, soon confluent and the centre of the thallus becoming a sorediate mass. Apothecia unknown in Tasmania, reported as to 2 mm diam., with narrowly ellipsoid ascospores, 8–15 × 2–4 µm (Ahti et al. 2011). Pycnidia not seen; conidia reported as 16–30 × 1 µm (Ahti et al. 2011).

Chemistry: atranorin, chloroatranorin, divaricatic acid and stenosporic acid (trace); medulla K–, KC–, C–, P–, UV+ pale bluish.

Widespread in cool climates in both hemispheres, especially on the wood and bark of old conifers. In Tasmania, it is known only from the western Central Plateau, where it occurs on dead, standing Athrotaxis cupressoides trees. It is very rare and, like P. ambigua, is listed as such under Tasmanian legislation. This species rather resembles a small species of Physcia, although no representatives of this genus are known to occur in such habitats. It is also similar to Imshaugia aleurites (Ach.) S.L.F.Mey., which is isidiate and contains thamnolic acid.

Northern shore of Lake Adelaide, 41°50’S 146°16’E, 1055 m, 2002, G. Kantvilas 74/02 (HO); Herods Gate, 41°49’S 146°17’E, 1200 m, 2002, G. Kantvilas 77/02 (HO); Long Tarns, 41°47’S 146°21’E, 1270 m, 2010, G. Kantvilas 38/10 (HO).

References