Myriolecis andrewii (B; de Lesd.) Sliwa, Zhao Xin & Lumbsch
Lecanora andrewii B. de Lesd.
Thallus of minute scattered granules, rounded and unequal in size, sometimes sparse and hardly visible, whitish to pale greenish. Apothecia 0.5-1.5 mm diam., usually numerous, sessile, more or less clustered, disc flat to concave, pale brown to brown-reddish, though seldom visible owing to the white pruine coating, exciple persitent, rather raised, uneven, contorted and crenulate, white. Ascospores simple, ellipsoid, often containing oil droplets, 9-13 x 5-6 µm. Photobiont: Trebouxia. Disc and exciple: C+ red-orange, K- or pale yellow, KC+ red, Pd+ red-orange. On neutral or slightly acid rocks in the xeric supralittoral zone. Not to be confused (although difficult) with Lecanora fugiens of which the thallus is brown-yellow or yellow-greenish, discs brown-yellowish to chestnut brown and sharing the same habitat. Easily confused with the very similar Lecanora dispersa which is not especially maritime, grows on alkaline substrata and with negative chemical reactions. N.B. Relationships with Myriolecis (Lecanora) semipallida (described subsequently) which is Pd- (though subject to variations on iron-rich substrata) would deserve a specific investigation. This is why the following pictures are presented with some circumspection.*