Ramalina rosacea (Massal.) Hepp, Flechten Europ. n° 356 (1857)

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 rosacea (Massal.) Hepp, Flechten Europ. n° 356 (1857)

var. Bas.: Ramalina polymorpha var. rosacea Massal., Schedul. Critic., fasc. IX: 157 (1856).

= R. bourgeana auct. europ., non Mont. ex Nyl.

Type.

Corsica, Cavallo, Lich. Exs. Ital. 228 (BM! - isotype).

Description.

Thallus saxicolous, firmly attached to the substrate (rock), formed of rigid, rather large lobes (2-8 cm large and 1-14 cm long) almost all attached with a single holdfast, lobes surface strongly reticulate-wrinkled. Apothecia usually present, marginal, usually at lobe extremities, with an outer exciple strongly scrobiculate. Ascospores straight or slightly curved, 1-septate, 10-12 × 3-5 μm. Pycnidia not found.

Chemistry.

Bourgeanic, norstictic, stictic and cryptostictic acid, PCR-1 and triterpenes.

Distribution and ecology.

Very rare, found on rocky sea-shores at two localities in the western parts of the Mediterranean Sea (France/Corsica and Spain; see below).

Remarks.

The original material was collected on the island of Cavallo, a small islet south of Corsica (France) and distributed through the Lichenes Italici Exsiccati, n° 288. The original publication (Schedulae criticae in lichenes exsiccatos Italiae IX n° 286-323) can be accessed through the permanent link http://mdz-nbn-resolving.de/urn:nbn:de:bvb:12-bsb10229836-1. We could examine the material preserved in BM: an original handwritten annotation is “Cavallo”. It matches very well the recent collection made on the very same islet by Gonnet et al. (2017) which we could examine (including by TLC and ITS sequence). The secondary metabolites of that material were identified as usnic, bourgeanic and salazinic acids ( Gonnet et al. 2017); we cannot confirm these results. Indeed, following the protocols designed by Culberson et al. (1981), we recognize the following as produced by the recent accession from Cavallo and two from Cabo de Gata (Spain): norstictic (+), stictic (++), cryptostictic (+++), and bourgeanic acid and triterpenes. Besides bourgeanic acid and the triterpenes, the main coumpound is the poorly known cryptostictic acid, easily confused in solvent G with salazinic acid (Suppl. material 8). We thus confirm the results of Krog and Østhagen (1980), who stated that this material contains depsidones in the stictic acid group. This confusion was the source of a nomenclatural imbroglio as to the identity of the material recently collected at Cavallo with R. bourgeana (Roux et al. 2019).

Quite interestingly, this easily recognized species (at least in the local Mediterranean context) is absent elsewhere in southern Corsica and northern Sardinia where two of us (MG and ES) looked carefully for it in several localities, including on other islets of the Lavezzi archipelago, the archipelago to which the island of Cavallo belongs. See for more at: http://www.afl-lichenologie.fr/Photos_AFL/Photos_AFL_R/Textes_R/Ramalina_bourgeana.htm.

The ITS barcode sequence of this material is strictly identical with that of a second population of that species found at the Cabo de Gata in SE Spain, a coastal locality most famous for its lichen flora ( Egea and Llimona 1994) and which also is the type locality of Ramalina clementeana ( Llimona and Werner 1975). Our results clearly demonstrate that it is a unique taxon, different from accessions from Macaronesia and referred to as R. bourgeana Mont. ex Nyl. (1870), following Krog and Østhagen (1980). All other reports of both species ( R. bourgeana and R. rosacea ) from the Mediterranean region are not confirmed and refer to other species, mostly R. tingitana .

Selected specimens examined.

France - Corsica, Cavallo Island; 41°22'N, 009°15'E; alt. 0-10 m; 2014; D. & O. Gonnet s.n. leg; rocky sea-shores (hb, LG DNA 4642); [DNA: MN788731 (ITS)]. Spain - Sierra del Cabo de Gata, path W of Torre de Vela Blanca to lighthouse; 36°43.82'N, 02°10.46'W; alt. 150 m; 2007; P. van den Boom 3835 leg; on exposed outcrops (hb van den Boom, LG DNA 426); [DNA: GU726357 (LSU), GU827316 (ITS), MN757014 (RPB1), MN757229 (RPB2)].