Lambiella plumbea Kantvilas, 2022

Kantvilas, Gintaras, 2022, The genus Lambiella Hertel (lichenised fungi) in Tasmania: new combinations, new species and a revised key, Phytotaxa 549 (2), pp. 209-218 : 214-215

Lambiella plumbea Kantvilas , sp. nov. Mycobank no. 844105

( Fig. 1C )

Most similar to Lambiella applanata (Kantvilas & Coppins) Kantvilas, L. globulispora (Sipman & Aptroot) Kantvilas and L. umbratilis (Kantvilas & Coppins) Kantvilas with respect to the thin, grey thallus and prominent black prothallus, but differing from these by the absence of lobaric acid, the minute apothecia, 0.075−0.13 mm wide, and subglobose to ellipsoid ascospores, 4–8.5 × 3–5 µm.

Type:— AUSTRALIA. Tasmania, Savage River Pipeline Road near Rapid River , S of the bridge, 41°16’S 145°20’E, 440 m elevation, on Atherosperma moschatum in rainforest, 31 January 2015, G . Kantvilas 227/15 (holotype − HO) .

Thallus crustose, effuse, lead-grey, rather glossy, 10−80 µm thick, areolate, spreading directly over bark or overgrowing epiphytic bryophytes and forming irregular, extensive colonies to 30 cm wide; areoles unevenly and patchily distributed over a black prothallus and forming a mottled mosaic of grey lichenised and black prothalline areas, in section ± unstratified, ecorticate, I−, KI−; prothallus crustose, frequently forming convex “islands” to 1.5 mm wide, in section dark brown and composed of amorphous, carbonised hyphae; photobiont a unicellular green alga (Chlorella- type) with cells globose to ellipsoid, 7–13 × 6−13 µm, in a gelatinous sheath 0.5–2 µm thick. Apothecia minute, 0.075−0.13 mm wide, lecideine, rather flattened and broadly adnate, single and roundish or crowded together in groups of up to 10 and then often squashed and deformed, formed mostly on the prothallus and only rarely on the lichenised thallus; disc plane, black, not gyrose; proper exciple black, persistent, entire, slightly higher than the disc, in section cupulate, 6−10 µm thick at the sides, opaque brown, ± unchanged in K, composed of rather amorphous, heavily pigmented, branched hyphae c. 2 µm thick. Hypothecium 10−20(−40) µm thick, pale to dark brown, mostly poorly differentiated from adjacent tissues. Hymenium 40−50 µm thick, ± hyaline but overlain by a rather lumpy, discontinuous redbrown epithecial layer, with streaks of pigment sometimes extending downwards between the asci to the hypothecium, intensely KI+ blue; paraphyses branched and anastomosing, c. 1 µm thick, with apices sometimes expanded to 2−3.5 µm; asci clavate, 8-spored, 22−40 × 9−13 µm, approximating the Trapelia type, with a thin, intensely amyloid outer wall, a prominently thickened tholus with weakly amyloid flanks and internal apical cap, and the ascoplasm apically truncate or concave and lacking an ocular chamber.Ascospores simple, persistently hyaline, non-halonate, thin-walled, subglobose to elllipsoid, 4– 6.2 –8(−8.5) × 3– 4.1 –5 µm (n = 70). Conidiomata not found.

Chemistry: no substances detected by TLC.

Etymology: The specific epithet alludes to the dull lead grey colour of the thallus.

Notes: This remarkable lichen has been known to the author for decades, but for most of this time was considered sterile and therefore unidentifiable. The convex, black patches of prothallus that occur across the thallus resemble the “rubbed down” ascocarps of a species of Arthoniaceae and were sectioned on numerous occasions but found to be composed exclusively of sterile, carbonised tissue. When apothecia were finally observed, their overall rareness, minute size, black colour and disposition on a concolorous prothallus explained why they had been overlooked for so long. A review of existing herbarium collections revealed several that possessed apothecia, albeit uncommonly.

The taxonomic affinities of this species were suspected on account of the superficial similarity of the thallus to a suite of other Tasmania species, namely L. applanata and L. umbratilis (both endemic to Tasmania) and L. globulispora (also in montane New Guinea). All have the same lead grey, effuse thallus, thinly dispersed over a black prothallus, although all but the new species contain lobaric acid. In all four taxa, the apothecia are adnate, and the ascospores tend to be subglobose to broadly ellipsoid but differ in the size ( Coppins & Kantvilas 2001). These taxa are compared in Table 1 . The new species is distinguished by the combination of extremely tiny apothecia, small globose to ellipsoid ascospores and the lack of lobaric acid.

Lambiella plumbea is relatively widespread and common in Tasmanian cool temperate rainforest, especially in communities of the thamnic type (nomenclature after Jarman et al. 1994). There it grows in deep shade on mature tree trunks, especially those with coarse, furrowed or flaky bark. Robust individuals of Phyllocladus aspleniifolius are frequently the preferred host, although the new species has also been observed on other trees, such as Atherosperma moschatum , Cenarrhenes nitida , Eucryphia lucida and Nothofagus cunninghamii . It tends to grow where other lichens are few or absent, but where bryophytes are frequent. It appears to be an aggressive coloniser, overgrowing and encrusting other species, especially leafy hepatics.

Additional specimens examined. AUSTRALIA. Tasmania: Sumac Road, Spur 2, S of Arthur River , 41°08’S 145°02’E, 170 m, 20 May 1981, G . Kantvilas 326/81 ( HO); Ben Ridge Road , 41°22’S 147°35’E, 850 m, 10 December 1981, G . Kantvilas 1107/81 ( HO); Anthony Road , 41°50’30”S 145°36’30”E, 550 m, 14 November 1992, G . Kantvilas 522/92 ( HO); ibid., 41°49’S 145°38’E, 480 m, 30 April 1993, G . Kantvilas 226/93 ( HO); Western Explorer Road , c. 1 km S of bridge over Donaldson River , 41°28’S 145°05’E, 220 m, 14 October 2003, G . Kantvilas 570/03 ( HO); Murchison Hwy near Mountain Creek , 41°47’S 145°34’E, 400 m, 18.xi.2008, G . Kantvilas 55/08 ( HO); Savage River NP, E side of Baretop Ridge, 41°18’37”S 145°26’51”E, 580 m, 29 January 2015, G . Kantvilas 36/15 ( HO); Badger Creek , c. 2.5 km S of Greystone Bluff, 43°06’S 146°02’E, 280m, 6 December 2016, G . Kantvilas 354/16 ( HO); track to Mt Wedge , 42°50’S 146°17’E, 600 m, 7 October 2017, G . Kantvilas 159/17 ( HO); Norfolk Road , N of Donaldson River, 41°28’S 145°05’E, 230 m, 19 March 2019, G . Kantvilas 58/19 ( HO) .

Figures

FIGURE 1. New Tasmanian Lambiella species. A. L. parvipsephota habit, showing rimose-areolate thallus on a black prothallus (scale = 1 mm) and detail of thallus areoles and apothecia (inset, scale = 500 µm). B−C. Asci and ascospores with amyloid parts after pretreatment in K stippled: L. parvipsephota (B) and L. plumbea (C). Scale = 10 µm.