Ramalina farinacea (L.) Ach. agg.
Thallus tufted, most often pendent, made of long branches, 3-10 cm long, narrow strap-shaped, 1-6 mm wide, slightly gutter-shaped, sometimes slightly branched, both surfaces identical, arising from a strictly delimited holdfast, pale greyish, pale grey-greenish, soredia numerous, farinose, clustered mainly towards the margins, arranged in rounded or ellipsoid soredia, 0.2-1 mm diam., whitish. Mostly infertile near the seashore, either marginal or laminal apothecia, saucer-shaped, sessile, disc white-ochre to pale pink. Ascii 8-spored, 40-50 x 18-25 µm according to our measures. Ascospores narrowly ellipsoid, pointed apices, straight, 1-septate, 8-15 x 5-7 µm according to literature, 10-15 x 5-7 µm according to our measures. Photobiont: Trebouxioid. Common, not especially maritime, on bark of trees and seldom on rocks (in that case, in the upper section of vertical walls on the foreshore or on exposed rocky ridges inland see Ramalina subfarinacea with digitate branching and soralia not forming discs) or on ground. Near the seashore, in highly exposed areas, not to be confused with Ramalina portuensis of which branches are large and swollen towards the base and with soredia in excavate lacerations on lobe surfaces.
It may be timely to consider Ramalina farinacea as a complex group since it is highly variable and numerous taxa have been described. According to French authors, the following chemotypes can be distinguished:
_ Ramalina farinacea var. farinacea = Ramalina farinacea chemo farinacea, straps pendent, thin, limited branching, less than 2 mm wide with marginal soralia; medulla and soralia: K-, Pd+ red.
_ Ramalina farinacea var. phalerata (Ach.) Ach. = Ramalina farinacea morpho phalerata branches more or less erect, straps 4-9 mm wide; medulla and soralia: K-, Pd+ bright red.
_ Ramalina farinaria var. multifida Ach. = Ramalina farinaria morpho multifida, straps highly branched notably towards apices, 4-5 mm wide; medulla and soraliea: K-, Pd+ bright red.
_ Ramalina farinacea var. hypoprotocetrarica (W. Culb.) D. Hawksw. = Ramalina farinacea chémo hypoprotocetrarica = Ramalina hypoprotocetrarica Culb. Atlantic, not especially on nutrient-rich substrate. Medulla and soralia: K-, Pd-, UV+ white-bluish.
_ Ramalina farinacea var. reagens B. de Lesd. = Ramalina farinacea chémo reagens. branches usually pendent, soralia and medulla: K+ yellow > red, Pd+ orange, UV-.
_ Ramalina farinacea chemo- , medulla and soralia : C-, K-, KC-, P-, UV-.
On the other hand, British authors have described four chemotypes:
Chemotype a : C-, K- or brown-orange, Pd+ red-orange, UV-.
Chemotype b : C-, K+ yellow > red, Pd+ yellow-orange.
Chemotype c : C-, K-, Pd-, UV+ bleuish.
Chemotype d : C-, K-, Pd-, UV-.
N.B. The morphotypes are not in concordance with the described chemotypes.
N.B.: This species is able to adapt to various climatic conditions, partly due to the coexistence of two different species of Trebouxia in its thallus, each one with a different optimum temperature growth. E. del CAMPO, S. CATALA, J. GIMENO, A. del HOYO, F. MARTINEZ-ALBEROLA, L. CASANO, M. GRUBE, E. BARRENO. "The genetic stucture of the cosmopolitan three-partner lichen Ramalina farinacea evidences the concerted diversification of symbionts".2013. FEMS Microbiol. Ecol. 83 (2013) 310-323.
N.B. According to some authors, the non sorediate fertile form would be, Ramalina implectens.