Coccocarpia delicatula Bungartz, Ziemmeck & Lücking
Mycobank MB 517757
Thallus foliicolous, foliose, rounded, up to 10 mm diam. Lobes thin, flat, 0.1–0.2 mm wide, linear but slightly widened towards the apex, isotomically branched and dissected, rather close. Upper surface blue-green when moist, plumbeous to bluish grey when dry, with thin, longitudina, white striae. Lower surface pale, with pale, unbranched, tapering, 0.2–0.4 mm long rhizines partly protruding from under the lobe margins and visible from above. Lobes densely isidiate; isidia laminal, dense, uniformly cylindrical, mostly unbranched to bifurcate, 0.1–0.3 mm long and 0.05–0.1 mm thick, in mature thalli covering most of the thallus interior. Apothecia not observed. Pycnidia not observed. Secondary chemistry: no substances detected by TLC.
This new species is close to Coccocarpia domingensis Vain. and the recently described C. neglecta Aptroot & Lücking (Lücking et al., 2007). All three species have very narrow, linear thallus lobes with fine, white longitudinal striae on the surface, and differ principally in the shape and arrangement of their isidia. In C. neglecta, the isidia are mostly marginal and rounded-squamiform, whereas C. domingensis has marginal, cylindrical to often slightly flattened isidia. C. delicatula produces laminal, always cylindrical isidia, identical to the type of isidia found in C. palmicola. The latter, however, has much broader, rounded thallus lobes.
The epithet refers to the delicate thallus compared to the common Coccocarpia palmicola (Spreng.) Arv. & D. J. Galloway, which has the same type of isidia.
Thus far only known from the Galápagos Islands, in the transition zone on Sán Cristóbal Island.
Type:—ECUADOR: Galápagos: Isla Sán Cristóbal, area W of Cerro Pelado on the way to El Ripioso, 0°52’S, 89°28’W, 400 m; transition zone, open Psidium guajava shrubland with Macraea laricifolia and dominant annual herb Malachra capitata, on bark and wood, dead twigs of Psidium guajava, sunny, wind- and rain-exposed; Aug 2008, Bungartz 8496 (holotype CDS-41142).
Additional specimens examined (paratypes):—None.
Sicut Coccocarpia domingensis sed isidiis cylindricis laminalibus differt.