Norw. J. Bot. 27: 185 (1980).
Protolog: Thallus saxicolus, opacus, subvirido-griseus, usque ad 1 cm altus, colonias confertas irregulariter expansas formans. Rami fragiles sparse ramosi, usque ad 1 mm lati, fistulosi, initio plus minusve teretes, demum subtus longitudinaliter findentes applanati, medulla exposita. Apices saepe revoluti. Cortex indistinctus, textura chondroidea inaequaliter crassa, medulla densa. Apothecia et pycnidia nulla. Acidum divaricaticum et acidum usnicum continens.
Protolog type data: Holotype: The Madeira Islands, Porto Santo, Pico de Facho, alt. 515 m, UTM grid ref. CB 7661, leg. Ø. Rustan 11 July 1978 (O).
Type locality: Portugal, Madeira Islands, Porto Santo, Pico de Facho, 515 m, 11.7.1978, Ø. Rustan, UTM grid ref. CB 7661 (O - holotype).
Type locality coordinates: 33°3'43?N, 16°21'23?W; 33.061944°, -16.356389°.
Molecular barcode: Data lacking.
Thallus: fruticose, opaque, pale green-grey, up to 1 cm high, forming dense, compacted, irregularly spreading colonies without a distinct, delimited holdfast. Laciniae fragile, simple or sparingly branched, up to 1 mm broad, fistulose, at first more or less terete, but soon flattening as the lower tissue layers split open almost to the base, exposing the medulla. Apices often revolute. Soredia absent. Cortex indistinct, chondroid tissue of uneven thickness, medulla dense. Apothecia and Pycnidia unknown (Krog & Østhagen 1980: 185).
Photobiont: Trebouxia.
Chemistry: Divaricatic acid, usnic acid (Krog & Østhagen 1980: 185).
Ecology: Saxicolous on silicious rock.
Distribution Type: Endemic to Porto Santo, Madeira Islands, Portugal.
Note: "The species is unique in the genus in that most laciniae split open and flatten into irregularly strap-shaped branches with a non-corticate underside. A similar condition was described for Ramalina reducta Krog & Swinscow from East Africa, a species not believed to belong in the subgeneric taxonomic unit Fistularia. In that species the lower tissue layers were reduced to a network of chondroid strands resting on the exposed medulla (Krog & Swinscow 1976). Most fistulose Ramalinas have a discontinuous or arachnoid medulla, giving the laciniae a semipellucid appearance. The dense medulla and opaque laciniae of R. confertula are less common, but are encountered, for example, in R. pusilla Prév. ex Duby. This species, however, has inflated laciniae, abundant apothecia, pycnidia with black ostioles, and sekikaic acid in the medulla. Ramalina confertula was collected near the summit of an old volcanic cone at 515 m altitude, where it grew together with R. nematodes (the dominant species), R. tingitana Salzm. ex Nyl., and Roccella spp." (Krog & Østhagen 1980: 185).
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