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Ramalina cuspidata (Ach.) Nyl. agg.

Synonyms:

Ramalina armorica  (Ach.) Nyl.

Ramalina atlantica  W L Culb.

Ramalina curnowii  Cromb.

Ramalina stenoclada WL. Culb.



Family: RAMALINACEAE

Habitat: Xeric supralittoral  zone

Description

    It seems reasonable to consider the hypothesis of a Ramalina cuspidata complex encompassing diffferent taxa, described under various names, as examplified by the rich and complex synonymy, but sharing a common general macroscopic aspect and the same habitat. It is possible to discriminate the different taxa on the basis of their morphological traits or their chemical properties but these two approaches give different results. A third appraoch based on molecular methods may contibute to clarify the issue but some prerequisites, seldom achieved up to now due to sampling problems and sample denomination variable according to the authors, are needed. It seems that there are significant differences at the level of apothecia of Ramalina cuspidata specimen; they are under investigation. Therefore we suggest to adopt a conservative approach and to present the three different chemotypes that are found in the field and to describe the three taxa that we are able to discriminate on the basis of morphological traits. Consequently, names and ranks given here are provisional and will have to be revised in the light of future results in the field of molecular taxonomy and phylogeny.

General description: Highly variable tufted species, found in our prospection area mainly under two different aspects: the pendent form, on vertical walls of rocks and the shrubby form at the top of rocks. Thallus, 10-15 cm long (pendent form) or 3-8 cm tall (erect form), made of narrow branches, terete (at least in part), 2-3 mm in section, apices thinned out, usually originating from a wide-spreading holdfast, tightly attached to the rock, surface bright, cream to pale grey-yellowish, pale grey-greenish. The holdfast is (except in case of alteration) black as well as the branches owing to the numerous pycnidia with black circular ostioles (charactaristic if visible). Apothecia rare, saucer-shaped, swollen, most often terminal. Ascospores colourless, ellipsoid, sometimes slightly curved, 1-septate, 11-16 x 4-6 µm according to our measures. Pycnidia black, conspicuous (not to be confused with the frequent erosion spots that may coexist). Photobiont: Trebouxia. 

Three chemotypes are described:

Ramalina cuspidata Chem a: C-, K+ yellow > red, Pd+ yellow-orange, UV -,  Norstictic acid.

Ramalina cuspidata Chem b: C-, K+ yellow-orange, Pd+ yellow-orange, UV-. Stictic acid.

Ramalina cuspidata Chem c:, C-, K-, Pd-, UV-. No lichenic acids

4 morphs may be distinguished on the basis of morphological traits, with all possible intermediate forms:

Ramalina cuspidata chem. cuspidata f. cuspidata : Base and end of branches black, section of branches more or less round; most often: C-, K + yellow +/- orange, KC + yellow, P + orange (Chem b).

Ramalina cuspidata chem. cuspidata f. armorica: Base and end of branches not especially black, section of branches more or less oval because some branches are more or less flattened; most often: C-, K + yellow +/- orange, KC + yellow, P + orange (Chem b).

Ramalina cuspidata chem. stenoclada: Base and tip of branches black, branches narrow and flat over a large part of their length, most often: C-, K + yellow then red, KC + golden yellow, P + orange (Chem a), quite similar to some forms of Ramalina siliquosa s.l.

Ramalina cuspidata chem. atlantica: Base and tip of branches black, branches narrow and more or less flat; C-, K-, KC-, P- (Chem c), very pale color; quite similar to some forms of Ramalina siliquosa s.l.

    Common but with a well delimited habitat, mainly on sides of little-lit and highly exposed rocks, usually lower on the foreshore than the other very common species, Ramalina siliquosa agg., but possibly mixed. If black pycnidia are absent, see Ramalina chondrina, but this spceies has not been found in our region. The erect forms of Ramalina cuspidata are sometimes almost impossible to distinguish from Ramalina siliquosa agg. notably from the altered forms and from the specimen dotted with black spots due to parasites like Stigmidium epiramalina (Vouaux) Haffelner.*

 







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