Ramalina siliquosa (Huds.) A. L. Sm. agg.

     It seems reasonable to consider the hypothesis of a Ramalina siliquosa complex encompassing diffferent taxa 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 produce different results. A third appraoch based on molecular methods may contribute 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. Therefore here we suggest to adopt a conservative approach and to present the different chemotypes that are found in the field (five upon 8) and to describe the different taxa on the basis of morphological traits. Names and ranks given here are provisional and will have to be revised in the light of future molecular taxonomy and phylogeny results and general synthesis with morphology and biochemistry.

  General description: Thallus coarsely tufted, 5-12 cm tall, erect or pendent according to habitats, highly variable in shape (erect forms are the most common). Primary branches arising form a wide-spreading holdfast, flattened, 2-8 mm wide, strap-shaped more or less regular, pale grey-greenish, pale green-yellowish, cream-ivory, surface matt, irregular, verrucose, nodulose more or less excavate by small crevices, sometimes lace-like in old altered specimen, soredia absent. Apothecia cup-shaped, lateral, seldom terminal., concolourous to the thallus, rather numerous in favourable habitat, to 8 mm diam. Pycnidia frequent, often clustered and forming coarse, whitish or hyaline nodulose irregularities, ostioles colourless, immersed in the thallus and hardly prominent or to the contrary warted or nodulose according to the different taxa. Ascospores broadly ellipsoid, or slightly kidney-shaped, 1-septate, 11-20 x 5-6 µm. Photobiont: Trebouxia. Four chemotypes are described here (but 8 taxa are described by some authors):

Chem. siliquosa = scopularum = chem. a: C-, K-, KC-, Pd+ orange, red-orange, UV- ; protocetraric acid. ( =Ramalina scopulorum p.p.)

Chem. crassa = chem. b.: C-, K+ yellow > red, KC+ red, Pd+ orange, yellow orange ; salazinic acid, UV-. ( =Ramalina crassa p.p.).

Chem. druidarum = Chem. c. : C-, K-, KC+ reddish, Pd-, UV+ pale blue; ( =Ramalina druidarum p.p.).

Chem. zopfii. : C-, K-, KC +/- yellow, Pd-, or C+/- yellow, K-, KC+/- yellow, Pd-, UV+ pale white blue. (Probably includes in the field Chemo d = Chem. O, without  lichenic acids and  C-, K-, KC-, Pd-, UV-, since chemical reactions, may they be positive, often are weak, results faints and difficult to interpret; in addition UV assay in the field is rather difficult).

Chem d = Chem 0 without lichenic acids: C-, K-, KC-, P-, UV-.

Chem. : conhydroprotocetraric acid ; C-, K+ yellow, KC+ yellow, Pd-.

N.B. Chemical spot tests used to characterize the different chemotypes are not efficient in all cases since their results may be variable including on a single apparently homogeneous colony, depending on genetic properties and micro-environments. We limit our presentation to well characterized taxa but numerous others are not taken into consideration due to improper knowledge.

    Widespread, on nutrient-rich acid rocks near the seashore in the xeric-supralittoral zone, in the spray zone, on top or sides of rocks sometimes quite far inland, on walls, and more rarely on bark of trees. N.B. The pending forms are sometimes very difficult to distinguish from Ramalina cuspidata agg. of which the pycnidia ostioles are black. The parasited forms with black dots are almost impossible to discriminate since other morphological traits are not always robust and many intermediate specimen between the two species (or group of species) may be found.

Tentatively, based on morphological traits for Chem crassa, see:

Ramalina siliquosa Chem crassa forme des rochers côtiers:.  Branches erect, often dichotomous branching (snake tongue like), cream to ivory colour.

Ramalina siliquosa Chem crassa forme des parois rocheuses verticales:  Branches more or less shrivelled, distorted and swollen, pustular, verrucose, grey-greenish.

Ramalina siliquosa Chem crassa forme à rameaux palmés. The twigs are flattened and shaped like deer horns (Moose!).