Ramalina chondrina J. Steiner

Öst. Bot. Z. 54: 352 (1904) fide IF

 

 

Description: Lichen. Thallus pendulous or decumbent, up to 20 cm long and 10 cm broad (terricolous forms much smaller), arising from a narrow holdfast. Laciniae filamentous, densely divergently, mainly dichotomously branched, pale green-grey, often partly black or reddish discoloured, smooth, terete, rarely weakly channeled near the holdfast, slightly flattened at points of branching, up to 1 mm broad at the base, tapering gradually, apices capillaceous, branchlets and ultimate branches bearing hook-shaped apical structures. Pseudocyphellae few, indistinct, or absent. Soralia absent. Cortex compressed, 10 - 15 µm thick, chondroid cylinder of almost even thickness, 100 - 150 µmm medulla of medium density. Pycnidia not seen. Apothecia very rare, lateral, disc 0.5 - 1.2 mm in diameter, flat to convex, spores 14 - 17 / 5 - 6 µm, straight or curved (Krog & Østhagen 1980: 264).

Photobiont: Data lacking.

Chemistry: No meduallary substances (Krog & Østhagen 1980: 264). Usnic acid as the only secondary product in samples from the Canary Islands as well as from Madeira (Follmann & Hernández-Padrón 1978: 373).

Ecology: Corticolous, terricolous or saxicolous. Sparse and scattered on trees in laurel forests and among rocks on shaded, north-facing slopes exposed to moist sea winds. In the Canary Islands between 550 and 900 m altitude (Østhagen 1976: 234, Krog & Østhagen 1980: 264).

Distribution type: Endemic of Madeira and the Canary Islands: Fuerteventura, Gomera and La Palma (Osthagen & Krog 1976). "Nach unseren zusätzlichen Aufsammlungen von Hierro und Tenerife darf ihre Verbreitung auf den Westkanaren trotz einiger Massenvorkommen (z.B. in den umfangreichen Beständen von Juniperus phoenicea L. im Westen von Hierro [Kassel 26361]) nur als zerstreut bezeichnet werden.

Taxonomy: The delimitation from Ramalina thrausta is in question. Krog & Østhagen (1980: 267) state: Ramalina chondrina is morphologically and anatomically very close to R. thrausta (Ach.) Nyl., a species with a wide distribution in the Northern Hemisphere. The main differences lie in that R. thrausta normally (but not always) contains an undetermined medullary compound which is never present in the Macaronesian specimens, its thallus is less robust, with thinner branches, and the branches are less divergent. Furthermore, its ecological requirements appear to differ somewhat from those of R. chondrina. Since these admittedly slight differences exist, and since R. thrausta is known only in the sterile state so far, we prefer to regard them as separate species for the time being".

Note:

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