Rufoplaca

Vondrák, Jan, Frolov, Ivan, Davydov, Evgeny A., Yakovchenko, Lidia, Malíček, Jiří, Svoboda, Stanislav & Kubásek, Jiří, 2019, The lichen family Teloschistaceae in the Altai-Sayan region (Central Asia), Phytotaxa 396 (1), pp. 448-450 : 448-450

Rufoplaca ( Figs 9 , 10 )

5 epilithic species recorded in the region. Thallus crustose, but sometimes strongly reduced and concentrated below apothecia. Vegetative diaspores are absent; apothecia are usually numerous. The genus is characterised by thin ascospores with thin septa. ( Xanthocarpia usually has ascospores with thin septa and a similar shape, but larger.) Anthraquinones are only in apothecia and Sedifolia-grey pigment is often present in the thallus. Almost confined to siliceous rocks, but rarely on dust impregnated wood. Two of five species in the region are lichenicolous. Taxonomy is not resolved. Our provisional taxonomic concept is based on the ITS DNA phylogeny and phenotypic differences recognized among specimens in different ITS lineages. Literature: Arup et al. (2013).

Rufoplaca arenaria sensu lato ( Fig. 10A ): Two specimens recorded at altitude 1120 m in humid non-alpine habitat. Substrate: granite (Vondrák 18693) and also mineralized wood of Larix (Vondrák 18371). Characterised by red apothecial margin being C+ purple (dissolved C solution required, see Vondrák & Wirth 2013). Chemical nature of the positive C-reaction is unclear; C+ substances (gyrophoric acid known from Rufoplaca or chlorinated anthraquinones) are absent from apothecia in the specimen Vondrák 18371 (analysed by LC-MS). Thallus is inconspicuous. Identity of Rufoplaca arenaria sensu stricto is unclear. The name R. arenaria is adopted from the concept by Arup et al. (2013).

Rufoplaca subpallida sensu lato ( Fig. 10B ): 6 localities at altitudes 400–1700 m in humid non-alpine or alpine sites. Substrate: siliceous rocks, rarely mineralized wood (Vondrák 19241). Characterised by thin but distinct brownishgrey epilithic thallus; traces of greyish thalline exciple are often observed; apothecia are typically with yellow-orange margin and brown-orange discs. ITS DNA sequences from Altai-Sayan region are closely related to sequences of American R. oxfordensis ( Fig. 9 ). Here we regard R. oxfordensis as contained within R. subpallida sensu lato.

Rufoplaca sp. 1 ( Fig. 10C ): 19 localities at altitudes 390–3000 m in all ecological categories. Substrate: various types of siliceous rocks, rarely on wood (not recorded on wood in the region). Most common Rufoplaca in the region. It is similar to R. arenaria sensu lato, but is characterised by orange apothecial disc and margin being C- (caution: C+ purple in concentrated hypochlorite solution, see Vondrák & Wirth 2013). In some specimens, mostly from upper altitudes, apothecial disc has yellow to olive tinged anthraquinone pruina ( Fig. 10C ). Rufoplaca sp. 1 as proposed in Fig. 9 does not form a homogeneous group in the ITS tree and probably includes more than one species.

Rufoplaca sp. 2 ( Fig. 10D ): In two localities at altitudes 2050–3000 m, in humid alpine sites (specimens Vondrák 9924, 18681). Substrate: gneiss, lichenicolous on lichen crusts ( Aspicilia , Acarospora , Miriquidica deusta ). Characterised by indistinct thallus, sometimes forming colourless necroses on host lichen; apothecia are orange, small and crowded, forming small spots on host thallus, sometimes containing Sedifolia-grey pigment in outer apothecial margin.

Rufoplaca sp. 3 ( Fig. 10E ): Single specimen recorded at altitude 500 m, in humid non-alpine habitat (Davydov 17245). Substrate: quartzite, lichenicolous on a crustose lichen (perhaps Aspicilia ). The specimen contains only fragments of thalli. Characterised by the yellow rim of true exciple that smoothly turns to grey thalline exciple (the yellow rim in apothecial margin is rare in Rufoplaca ). Thallus is thin, pale, without obvious pigmentation. Apothecia are orange, reaching 1 mm diam. (Usual size of mature apothecia in Rufoplaca is about 0.5 mm diam.)

Figures

FIGURE 9. Bayesian phylogenetic reconstruction of Rufoplaca using the ITS DNA locus. Sequences from the Altai-Sayan region are in grey squares.

FIGURE 10. Rufoplaca (A–E). A, Rufoplaca arenaria sensu lato (Vondrák 18371; on mineralized wood) with apothecia more red than orange; B, Rufoplaca subpallida sensu lato (Vondrák 9929) with a distinct grey thallus, brown-orange apothecial disc and pale orange apothecial margin; C, Rufoplaca sp. 1 (Vondrák 12663) with slight olive tinge in apothecial discs; D, Rufoplaca sp. 2 (Vondrák 9924) forming bleached necrosis on Acarospora sp.; E, Rufoplaca sp. 3 (Davydov 17245) with large apothecia and a yellow outer part of the true exciple.All bars, 1 mm.