Rinodina aspersa (Borrer) J. R. Laudon subsp. aspersa
Rinodina aspersa (Borrer) J. R. Laudon
Rinodina fatiscens (Th. Fr.) Vain.
Thallus crustose, often barely developped, made of scattered or contiguous areoles on a black prothallus, areoles flat or slightly convex with rounded edges, greyish, dull grey, whitish, pale brownish. Prothallus well developed and distinct between areoles, slightly fimbriate on margin (suggesting dead tree branches), blackish tending toward black. Thallus more or less covered with flat to barely globose soralia, 0.5-1 mm diam., pale greenish, grey-greenish, grey-yellowish, soredia farinose, concolourous. Most often sterile, or with apothecia more or less sessile, 0.5-1 mm diam., disc pale brown, exciple persitent, concolourous to the thallus. Ascii 70-80 x 20-30 µm according to our measurements. Ascospores broadly ellipsoid, apices almost hemispherical, locules not angular, 1-septate, 15-20 x 13-20 µm according to literature, 13-19 (22) x (7) 8-14 µm according to our measurements. Photobiont : Trebouxia. Soralia : C+ red-orange, K+/- yellow, Pd+/- yellow, UV-. One of the rare species living on hills but with oceanic and maritime affinities, growing on siliceous rock or pebble along the shore but also on more or less vertical rocks inland, usually in small groups in the company of different species of Porpidia or Rhizocarpon. N.B. The appearance is very variable according to habitat, varying from forms only made of globose soredia placed on a black prothallus, to forms densely areolate with a few apothecia.
N.B. This species shares with Rinodina atrocinerea the same chemical reactions profile; some authors rank them as two sub-species : Rinodina aspersa subsp. aspersai with soredia and barely fertile and Rinodina aspersa subsp. atrocinerea without soredia and well fertile, in accordance with what we have retained here. However we prefer, awaiting a study that will precise the rank of these taxa, to conserve Rinodina atrocinerea more grey and very "maritime". We also present Rinodina aspersa s.l. forme intermédiaire littorale with an intermediate thallus between Rinodina aspersa subsp. aspersa et Rinodina aspersa subsp. atrocinerea. N.B. Careful to Fuscidea praeruptorum that can sometimes show a similar appearence.*