Norw. J. Bot. 27: 198 (1980).
Basionym: Ramalina scopulorum var. nematodes Nyl., Bull. Soc. Linn. Normand., Ser. 2, 4: 157 (1870).
Synonyms: Index Fungorum
Protolog: Data lacking.
Protolog type data: "Ins. Canar.", Portu Sanctu (H-NYL 36988 - lectotype, PC - isolectotype). Lectotypified by Krog & Ø,sthagen (1980: 187). [TLC: salazinic acid, usnic acid (+)]
Type locality: Portugal, Madeira Islands, Porto Santo (H-NYL 36988 - lectotype, PC - isolectotype).
Type locality coordinates: 33°3'43"N, 16°21'23"W; 33.061944°, -16.356389°.
Molecular barcode: Data lacking.
Thallus: fruticose, rigid, subpendulous to pendulous, up to 12 cm long. Holdfast distinct, delimited, up to 1.5 cm in diameter. Laciniae matt, pale green-grey near the base, brown-grey to reddish brown distally, sparingly dichotomously to irregularly branched, either terete, 0.2-1.5 mm in diameter, or flattened and then up to 5 mm wide, attenuate, sometimes with hook-shaped apices, or flat and more or less dilacerate. Pseudocyphellae prominent, longitudinally arranged, anastomosing, elongate and linear or irregularly spreading. Proper cortex indistinct of irregularly spreading. Proper cortex indistinct or absent. Strands of chondroid tissue interspersed with dense medullary tissue, algal cells present throughout the medulla. Apothecia rare, seen only in the type collection where they were lateral, shortly stipitate, with ochraceous, pruinose discs. Spores one-septate, relatively thin-walled, straight to slightly curved, (12)14-16 x 4-5 µm. Pycnidia unknown (Krog & Østhagen 1980: 187).
Photobiont: Data lacking.
Chemistry: Two chemical races:
Ecology: Saxicolous.
Molecular data: Genbank
Distribution: Database
Note: "Although the type specimens of R. nematodes contain salazinic acid, all Rustan's collections, as well as two specimens in PC (one of them, in Herb. Lenormand, undoubtedly part of the original collection), contained protocetraric acid as their diagnostic medullary substance. The two chemotypes are morphologically indistinguishable" (Krog & Østhagen 1980: 187).
Race I: Salazinic acid, usnic acid (+) in type specimen (Krog & Østhagen 1980: 188).
Race II: Protocetraric acid, usnic acid (+) (Krog & Østhagen 1980: 188).
