Parmeliella Müll.Arg.
Type : Parmeliella triptophylla (Ach.) Müll.Arg. [=Lecidea triptophylla Ach.]
Description : Thallus crustose–squamulose to foliose, orbicular to spreading, closely or loosely attached, often with a prominent blue-black to black (rarely pale or buff), marginal, byssoid prothallus of projecting, felted, silky rhizohyphae. Lobes laciniate to microphylline and ±lobulate–squamulose, flat to convex, discrete to imbricate. Upper surface smooth or wrinkled–plicate, matt, glossy or ±scabrid or pubescent, with or without soredia, isidia or phyllidia, dark grey-blue to fawnish, brown-grey, olivaceous or blackish. Margins entire to phyllidiate or sorediate or incised–crenulate. Medulla white. Photobiont cyanobacterial, usually Nostoc in clusters not penetrating into base of hymenium. Lower surface tomentose or ± rhizinate, usually pale. Ascomata apothecia, sessile, often frequent, rounded, biatorine; disc plane to concave, epruinose, red-brown to brown, rarely blackish; proper exciple distinct, pale; thalline exciple rarely present (absent in NZ taxa), crenulate, obscuring proper exciple. Hymenium hyaline, I+ persistent blue. Asci with a distinct apical amyloid plug. Ascospores ellipsoidal, smooth, thin-walled, occasionally apiculate at one or both ends; exospore thin or absent. Conidiomata pycnidia. Chemistry nil.
Key
Parmeliella is a genus of c. 64 species worldwide (Jørgensen 2003c, 2004a: 243–247, 2004e; Jørgensen & Arvidsson 2004), more diverse and speciose in the Southern Hemisphere (in warm-temperate to subtropical habitats) than in the Northern Hemisphere. It is included in the family Pannariaceae (Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005). However, Henssen (1997: 79) opines that both Parmeliella and Santessoniella do not belong in this family, because of differences in the ascus type, a position also supported by Jørgensen (2000d: 670), and by recent molecular studies (Ekman & Jørgensen 2002). Currently, the precise generic limits and affiliation of Parmeliella remain unclear. The Flora treatment (Galloway 1985a: 344–350) discussed nine taxa of which three were subsequently transferred to other genera (Degelia, Fuscoderma, Leioderma). Recent research on Australasian and South American taxa confirms that species of Parmeliella have a number of characters in common, viz. squamulose thalli; orange-brown, biatorine apothecia lacking photobiont cells; little or no chemistry; a persistent I+ blue hymenium; and amyloid plugs in the ascus apex (Jørgensen 1998b). Two sections are recognised in the genus, viz. Parmeliella sect. Parmeliella and Parmeliella sect. Austroparmeliella P.M.Jørg. (Jørgensen 2004a: 243).
The present treatment recognises 14 taxa in the New Zealand flora, though the genus is still incompletely known here. Taxa colonise a variety of habitats from s.l. to 2000 m and may be corticolous, muscicolous, saxicolous or terricolous, with the majority of species occurring in lowland forest or scrub habitats of high humidity and moderate to deep shade. For recent accounts of Parmeliella and its relationships with other genera in the Pannariaceae see Jørgensen & Galloway (1992b: 271–278), Jørgensen (1998b, 2000b, 2000d, 2001b, 2002c, 2003a, 2003b, 2004a), Makhija & Adawadkar (1999) and Jørgensen & Kashiwadani (2001b).
Parmeliella mucorina Zahlbr. (Zahlbruckner 1941: 272; Galloway 1985a: 348) is referable to Phyllopsora microdactyla (q.v.).
