Ramalina krogiae Guissard & Serus ., 2020

Spjut, Richard, Simon, Antoine, Guissard, Martin, Magain, Nicolas & Serusiaux, Emmanuel, 2020, The fruticose genera in the Ramalinaceae (Ascomycota, Lecanoromycetes): their diversity and evolutionary history, MycoKeys 73, pp. 1-68 : 1

Ramalina krogiae Guissard & Serus. sp. nov. Fig. 11A, B

Diagnosis.

Ramalina krogiae is recognized by its saxicolous habitat, ascending, 1-2 dichotomous branched, rigid lobes, producing abundant granules, but no genuine soralia, nor apothecia, producing divaricatic acid and endemic to the Canary Islands and Madeira archipelagoes

Type.

Spain - Canary Islands, La Gomera, W of Arure, N of Ermitago de Santo; 28°08.10'N, 017°19.23'W; alt. 825-830 m; 04.2009; E. Sérusiaux s.n. leg; subvertical outcrops in open matorrales; (LG DNA 666! - holotype; TFMC! - isotype) [TLC: divaricatic and usnic acid; DNA: MN811446 (LSU), MN811250 (ITS), MN757049 (RPB1), MN757257 (RPB2)]

Description.

Thallus saxicolous, ascending, usually rigid, when well-developed up to 3-4 cm high, usually with 1-2 dichotomous branching in the upper half of the branch, 3-4 mm large at most, usually less, branches contorted or irregularly twisted, small dissected and elongated lobes (small laciniae) usually present, together with tiny rounded or irregularly shaped granules, these granules sometimes abundant; cortex locally and usually irregularly broken off, but no typical production of soralia observed. Apothecia rare to abundant, lateral, disc usually strongly concave ("wide open" apothecia rarely seen) with a scrobiculate outer cortex, margins of the disc usually with cortex interruption and production of tiny granules. Ascospores straight or slightly concave, 1-septate, 9-13 × 4-5 µm. Pycnidia not found.

Chemistry.

Divaricatic and usnic acid, triterpenoids.

Distribution and ecology.

On exposed rocks at low elevation, in the Canary Islands and the Madeira archipelago.

Etymology.

Epithet chosen after our most distinguished colleague Prof. Hildur Krog (1922-2014), author, inter alia, of a remarkable and detailed revision of the genus Ramalina in the Canary Islands ( Krog and Østhagen 1980).

Remarks.

Besides its distinct geographical range (Mediterranean region vs. Canary Islands and Madeira archipelago), the morphologically and chemically similar R. requienii can be distinguished by its usually larger lobes with sublinear pseudocyphellae and especially the lobes extremities rather typically labriform, with a lower surface with large patches of disrupted cortex and production of coarse soralia. In typical populations of R. krogiae , no such labriform and slightly, but distinctly, expanded lobes are formed and tiny granules produced on or around the rather large cortex interruptions at the lobe extremities are not observed. Therefore, the distinct phylogenetic relationships of R. krogiae , as well as its disjunct distribution, are complemented by morphological features, which albeit rather cryptic can be easily detected with some taxonomic expertise.

Additional specimens examined.

Portugal - Madeira, Ponta de São Lourenco; 32°44'N, 16°40'W; alt. 150 m; 05.04.2007; D. Ertz 10520 leg.; rock outcrop near the sea; (BR, LG DNA 431); [DNA: GU726360 (LSU), GU827319 (ITS), MN757017 (RPB1), MN757232 (RPB2)]. Portugal - Porto Santo, between Pico de Castelo and la Capela de Nossa Senhora da Graça; 33°04.41'N, 016°19.37'W; alt. 200-220 m; 04.2007; M. Dewald, A. Hambuckers & E. Sérusiaux leg.; outcrops in pastures; (LG DNA 459); [DNA: MN811437 (LSU), MN811241 (ITS), MN757040 (RPB1)].

Figures

Figure 11. Species in Ramalina A, B R. krogiae (holotype) C-E R. requienii (France, Corsica). Scale: 1 cm (A-D); scale in E identical to D. Photographs by E. Serusiaux.