Flavoparmelia caperata (L.) Hale forma caperata
Parmelia caperata (L.) Ach.
Thallus rosette-shaped, loosely appressed, to 20 cm diam., made of lobes, 5-12 mm wide, enlarged and rounded at apices, transversally wrinkled or crumpled (as badly ironed), grey-yellowish, yellowish when dry, green-yellowish, green-apple when moist, often coarsely corrugate, surface entirely covered, and notably towards the center, with granular soredia around pustulate soralia, 0.5-3 mm diam., lower surface blackish towards the center, margins brownish with simple rhizines. Uncommon apothecia, pustulous at first, then sessile, to 8 mm diam., disc concave, brown-red, exciple markedly sorediate, concolourous to the thallus. Utriform asci, 50-65 x 25-30 µm according to our measurements, with 8 spores. Colorless, elliptical spores, 15-24 x 9-12 µm according to the literature, 16-20 x 8-11 µm according to our measurements. Photobiont: Trebouxioid. Cortex : K-, Medulla and soredia: K- or dull yellow, KC +/- red or slightly orange, never red,, KC+/- reddish, Pd+ pale red-orange. Species not especially maritime but very frequent in our prospection area on the bark of the trunks and large branches of trees (the most frequent corticole form presented here) but also on the rocks: Flavoparmelia caperata forme saxicole or in the heather of the aerohaline zone : Flavoparmelia caperata forme des landes aérohalines. N.B. Not to be confused (although rather difficultly in absence of chemical spot tests) with the much rarer Flavoparmelia soredians that has clear oceanic trends and a medulla K+ yellow turning red, the two species potentially growing in combination. N.B. When pseudocyphella can be observed, and C+ red, see Flavopunctelia flaventior.
Several morphs of this highly variable species are worth to be mentioned, but these are simple forms without much taxonomic interest::
Flavoparmelia caperata f. papillosa of which the thallus and apothecia exciple are covered with small verrucose isidia, 0.2-0.5 mm diam. can give soralia. Often more common than the type in some high exposure areas.,
Flavoparmelia caperata f. laevissima of which the thallus is devoid of verrucose isidia and of soredia, not rare that comes mixed with type..