Ramalina stoffersii Sipman
Mycobank MB 517809
Thallus pale yellowish green, 3–10 cm high, forming ca. 3–20 cm wide, rather intricate, subpendulous cushions; prothallus spreading and giving rise to swarms of thallus lobes, but often decayed and the thallus attached by secondary attachment spots on the thallus lobes; thallus lobes linear, rather regularly dichotomously branched up to over 10 times over their whole length, applanate, ca. 1–2 mm wide and ca. 0.3 mm thick, with flat to slightly convex sides, rarely in part canaliculate or subcylindrical; pseudocyphellae present, linear, mainly on the lobe margins and there to over 1 cm long and causing the lobes to become rectangular in section, also frequent on the sides but there shorter and rarely over 2 mm long; lobe upper parts and tips sometimes with minute lobules, often densely branched, about 0.1 mm wide, to over 1 mm long, with hooked tips; soralia present, marginal, farinose, rounded to elongate, ca. 0.2–0.5 mm in diam., sometimes warty, with ca. 50 µm wide soredia. Apothecia and pycnidia unknown. Secondary chemistry: usnic and divaricatic acids.
Ramalina is among the largest genera of macrolichens but nevertheless new species are still being discovered regularly. The Antilles, where R. stoffersii was discovered, are promising for diversity in the genus Ramalina, because the genus as a whole shows considerable insular endemism, e.g., on the Canary Islands (Krog & Osthagen, 1980), the Galápagos Islands (Aptroot & Bungartz, 2007), and St. Helena (Aptroot, 2008). Moreover, the Neotropics in general, in spite of some regional treatments (Kashiwadani, 1987; Kashiwadani & Kalb, 1993) appear to be very incompletely explored, as suggested by, e.g., the published results from unfinished studies in Venezuela by Morales Méndez and collaborators (Marcano & Morales Méndez, 1994). The representation of the genus on the Antillean Island Puerto Rico has received considerable attention (Landron, 1972; Harris, 1989), and most of the specimens collected by the author on the islands Saba and St. Eustatius fit well the indicated species. Only one group of specimens lacked description because it was misunderstood, and it is described here. Ramalina stoffersii is morphologically very similar to R. dendroides Nyl., which grows in the same localities. In fact, Landron (1972) was already aware of its existence but treated it as a chemically deviant population. The specimens collected on the Antillean islands Saba and St. Eustatius made clear that it involves two distinct species with a different mode of vegetative reproduction. R. stoffersii is a truly sorediate species producing soredia in rounded, marginal, sometimes slightly tuberculate soralia. R. dendroides produces larger, corticate granules on top of short, ca. 1–2 mm long, cylindrical, lateral branchlets. These morphological differences may be obscured in poorly developed specimens and much abraded herbarium material. The combination of linear thallus lobes with marginal soralia and divaricatic acid seems to occur otherwise only in R. nervulosa (Müll. Arg.) Des Abb. (Stevens, 1987), but that species lacks the prominent marginal peudocyphellae and has larger, more elongate and excavate soralia. The primary species related to both R. dendroides and R. stoffersii is probably R. peranceps Nyl., or if one prefers to consider this a chemical strain, R. anceps Nyl. The presence of divaricatic acid was tested in all listed specimens and confirmed by cochromatography with Evernia divaricata (L.) Ach. using standard TLC procedure (Orange et al., 2001, solvents A, B' and C).
The new species is named after the late A. L. Stoffers (Utrecht, The Netherlands), who raised my interest in Antillean lichens.
Known from the Lesser Antillean islands of Saba and St. Martin and from Puerto Rico (Landron, 1972). The species occurs in maritime environment below ca. 500 m, mainly on andesite boulders and stone walls among cultivated fields, once one a trunk of a Mammea americana tree. Perhaps it is more commonly epiphytic in more natural vegetation.
Type:—LESSER ANTILLES: Saba: Lower Hell's Gate, trail head of trail to Sulphur Mine; 17°39’N, 63°14’W, 300 m; steep slope with scrub and rock outcrops, on andesite rock; Mar 2007. Sipman 54767 (holotype NY; isotype B).
Additional specimens examined (paratypes):—SABA: Windwardside; 17°38’N, 63°14’W, 400 m; Sipman 15176 (B). Along path Windwardside-Rendez Vous; Sipman 15185 (B), 15238 (B). Hell’s Gate, on steep N-facing slope above the sulphur mine; Sipman 15384 (B). North Coast trail from parking area in Lower Hell's Gate to Crab Rock, mostly within Saba National Park; Buck 50882 (NY), 50884 (NY). Village of Windwardside; Buck 50942 (NY). ST. MARTIN: Dutch Cul de Sac, Emilio Wilson estate, Sentry Hill; Buck 50963 (NY).
A Ramalina dendroide persimili differt soraliis farinosis, acido salacinico absente et acido divaricatico presente.