Thelenella Nyl.
Type : Thelenella modesta (Nyl.) Nyl. [=Verrucaria modesta Nyl.]
Description : Thallus crustose, superficial to subimmersed, membranous, to rimose or areolate, prothallus often visible. Photobiont green, globose, chlorococcoid. Ascomata perithecia, immersed in thalline warts, globose to ±top-shaped. Involucrellum absent. Centrum globose to transversely ellipsoidal. Exciple hyaline to pale-brown at base becoming brown to dark-brown at sides. Hamathecium of paraphyses and periphysoids multicellular, richly branched and anastomosing. Periphyses absent. Asci ±cylindrical, 4–8-spored, bitunicate, without apical apparatus in tholus, I−, wall uniformly thick. Ascospores uniseriate in ascus, muriform to submuriform, colourless, rarely becoming pale yellow-brown, ellipsoidal or elongate-ellipsoidal, often broadening towards one end. Conidiomata pycnidia, Roccella -type. Conidia thread-like.
Thelenella, included in the family Thelenellaceae (Mayrhofer 1987; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005), is defined by a crustose thallus, often immersed perithecia, thick-walled bitunicate asci, a hamathecium of branched and anastomosing paraphyses and periphysoids, colourless to pale-brown, submuriform to muriform ascospores, and conidiomata with filiform conidia. An open involucrellum is present in only a few species. Most of the saxicolous taxa, with the exception of T. brasiliensis and T. luridella, appear to be restricted to maritime or at least oceanic habitats (Mayrhofer & McCarthy 1991). The genus comprises c. 21 widespread species (Mayrhofer 1987, 2002; Mayrhofer & McCarthy 1991; Etayo & Mayrhofer 2003; Fryday & Coppins 2004) of which one is present in New Zealand.
