APTROOTIA ¹

Gintaras Kantvilas ²

Aptrootia Lücking & Sipman, in R. Lücking et al., Lichenologist 39: 188 (2007).

Type: A. terricola (Aptroot) Lücking, Umaña & Sipman

Thallus crustose, corticate or ecorticate. Photobiont Trentepohlia. Ascomata perithecia, globose to ampulliform, solitary, immersed in the substratum and exposing only the ostiolar region; perithecial wall black, in section completely carbonised, not differentiated internally. Ostiole apical. Interascal hyphae richly branched and anastomosed, sometimes inspersed, embedded in a non-amyloid, gelatinous matrix. Asci clavate to cylindrical, 1(–2)-spored, non-amyloid, at maturity lacking an ocular chamber. Ascospores dark brown when mature, broadly ellipsoid, fusiform or bacilliform, muriform, KI+ blue, typically with a gelatinous sheath. Conidiomata unknown. Chemistry: nil.

A genus of three widely scattered species (Costa Rica, New Guinea and Australasia) found on soil or bark in areas of high rainfall. It has been segregated from the related but heterogeneous genus Laurera, chiefly on the basis of its brown ascospores, supported by DNA-sequence data.

Key references: McCarthy & Kantvilas (1993); Lücking et al. (2007); Aptroot (2009); Aptroot & Lücking (2016).

1 Aptrootia robusta (P.M.McCarthy & Kantvilas) Aptroot

Fl. Australia 57A: 661 (2009); —Laurera robusta P.M.McCarthy & Kantvilas, Lichenologist 25: 51 (1993). Type: Tasmania, Crater Peak, 41°39’S 145°56’E, on soil, lichens and other cryptogams in rock crevices in alpine heathland, 1200 m, 16 February 1984, G. Kantvilas 405/84 & P.W. James (holo—HO!; iso—BM!).

Thallus ecorticate, continuous to sparingly rimose, smooth to irregularly rugulose-verruculose, matt or slightly glossy, pale to dull greenish grey or brownish grey, 50–100(–120) µm thick, forming extensive continuous colonies to 15 cm wide; photobiont with cells irregularly roundish, 10–30 µm wide. Perithecia 0.9–1.5 mm wide, typically almost entirely immersed, occasionally semi-emergent, becoming excavate with age; ostiole 50–100 µm wide. Interascal hyphae not inspersed, 0.5–0.8 µm thick. Asci 1-spored, 225–320(–400) × 70–120(–150) µm. Ascospores 145–239–360 × 65–100–140 µm, usually elongate to broadly ellipsoid to clavate, non-halonate, with 24–54 transverse and 12–20 longitudinal septa.

Widespread but rarely common on peaty, wet soil over metamorphosed Precambrian sediments and Ordovician conglomerate in the mountains of the west and south-west; also on granite on the higher pinnacles of Freycinet Peninsula. It is also known from a single locality in southern New South Wales (Pigeon House Mtn). This species is found in heathland and moorland in sheltered rock crevices and overhangs, on well-drained, steeply-sloping banks or on moist, flat ground. It is clearly very vigorous and competitive, and rapidly encrusts other small plants in its path. The black, gaping ostioles or excavate ‘craters’ of old, empty perithecia are very conspicuous; fertile thalli are not commonly encountered. Aptrootia robusta is one of several terricolous lichens with relatively huge ascospores that occur on soil on the mountains of the south-west; others include Lepra gymnospora, Pertusaria flavoexpansa and Melanotopelia rugosa.

Mt Amos, 42°09’S 148°18’E, 480 m, 1991, G. Kantvilas 290/91 (HO); Sentinel Range, eastern summit, 42°52’S 146°15’E, 960 m, 1992, G. Kantvilas 95/92 (HO); summit of Black Bluff, 41°27’S 145°57’E, 1335 m, 2000, G. Kantvilas 131/00 (HO).

References