Lichens marins - Protoparmelia montagnei (Fr.) Sancho & Crespo s.l.

Thallus, more or less thick, variable, surface irregular, brown-greyish, pale brownish with olive-green tinge (never warm colour), prothallus distinct when young and parasite, blackish. Apothecia numerous, 0.5-1.5 mm diam., immersed or sessile, disc flat, matt, dark brown, sepia, exciple concolourous or paler. Ascii 8-spored, 40-50 x 12-15 µm according to our measures. Ascospores oblong to ellipsoid, apices rounded, 9-13 x 2-4 µm according to literature, 8-13 x 2.5-4 according to our measures. Pycnidia numerous. Photobiont: Trebouxioid. Three chemotypes are known (chemical reactions are performed on the upper part of medulla in order to avoid contamination by parasited lichens):

Chemotype 1 = chemo aquilina: C + red, K-, KC+ pink, P-, UV+ white. "Maritime" taxon occuring on the siliceous rocks of the seawater projection zone.

Chemotype 2 = chemo montagnei: C -, K-, KC+ pink, P-, UV+ white. Taxon also maritime but can come further inland.

Chemotype 3: C + red, K-, KC+ pink, P- and UV -.

Fairly common species (chemo aquilina) on the rocks of the xeric supralittoral zone subjected to seawater projections where this species parasitizes crustose lichens, at least during its first stage of development; quite rare on the siliceous rocks of central Brittany (chemo montagnei). See a parasitic form: Protoparmelia montagnei forme parasite de Aspicilia cupreogrisea.

N.B. Some old specimens seem to regenerate by giving bud-like on old thalli, see: Protoparmelia montagnei chemo aquilina forme de régénérescence.

Important note: this species is extraordinarily variable and probably contains several taxa because, in addition to the 3 chemotypes, there seem to exist several macroscopic aspects (morphotypes), some of which are difficult to distinguish from some plain forms of Protoparmelia badia which has warmer colorations and spores with pointed apices and which is a collinean to montane species. Currently these morphs are under investigation and seem to interact with the host crustose lichen (by incorporation of the host's photobiont?), In addition, intermediate specimen or chimera may be found.