Family: Parmeliaceae |
Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2. Life habit: lichenized, sometimes lichenicolous when young Thallus: crustose, rimose, warted or areolate, usually corticate, rarely scurfy and not corticate surface: pale gray brown to dark or chestnut brown, often glossy, sometimes isidiate, sometimes with thalloconidia cortex: composed of branched, short-celled, anticlinal hyphae, often terminated by brown pigmented "hoods", and usually overlain by a distinct, hyaline epicortex medulla: usually well defined, with thick-walled hyphae, I- photobiont: primary one a trebouxioid green alga, secondary one absent; the cells sometimes dividing internally to form autospores. usually forming a well-defined layer Apothecia: arising from within areoles or warts, immersed to sessile, usually glossy disc: brown, often darker than margin, epruinose margin: +concolorous with thallus, 12-30 µm thick, with a medulla filled with algal cells and usually a well-defined cortex similar to that of thallus amphithecium: with a well defined cortex similar to thalline one, with a medulla filled algal cells exciple: biatorine, hyaline, often forming a cupula hymenium: mostly 50-90 µm tall, I+ blue; paraphyses: simple or occasionally forked, septate, often over 2.5 µm thick, sometimes with slightly wider apices, but usually each covered by a swollen gelatinous "hood" that often contains a brown "cap", regenerated by insertion of new paraphyses, while the old paraphyses form an epinecral layer by gelatinization; hypothecium: hyaline asci: clavate, under 60 µm long, +Lecanora-type, with or without an ocular chamber, but always with a distinct, non-amyloid apical cushion, 8-spored ascospores: hyaline, simple (sometimes a few 1-septate when old), ellipsoid or more usually fusiform-ellipsoid to oblong-ellipsoid to oblong, 7-13 x 2-7 µm; wall: smooth, lacking a distinct perispore Pycnidia: immersed, globose to ovoid, not compartmented; wall: hyaline except for brown pigmentation around the ostiole; conidogenous cells: few-celled, often slightly branched, arising on branched conidiophores or in chains, +cylindrical, enteroblastic, acrogenous or pleurogenous conidia: hyaline, simple, either bacilliform, short-acicular, or curved and thread-like Secondary metabolites: orcinol depsides, orcinol depsidones, ß-orcinol depsidones, terpenoids, aliphatic acids, and various unknowns Substrate: on rock or sometimes bark Geography: Europe, Asia and North America. Notes: Protoparmelia is separated from Lecanora by its brown pigmentation, generally smaller (especially narrower) ascospores, straight conidia borne both acrogenously and pleurogenously, lack of atranorin, and somewhat different ascus type [see Hafellner (1984) resurrection of the genus based on Choisy (1929)]. Miyawaki (1991) argued that Protoparmelia badia belongs in the Parmeliaceae because: 1) its continuous algal layer extends from the thallus into the thalline margin of the apothecia, surrounding the excipulum proprium in a "saucer-shaped layer"; 2) its cupular excipulum proprium is composed of meristematic short cells; 3) its conidia are rod-shaped and produced laterally [conidiophores type VI of Vobis (1980); Parmeliatype in the sense of Glück (1899)]; and 4) the presence of lobaric acid (an orcinol depsidone), which is very unusual in the Lecanoraceae. However, the genus Protoparmelia as currently delimited is rather heterogeneous; some of the species differ rather strongly from P. badia, and many do not have a cupular excipulum (Poelt and Grube 1992). According to Rambold (1989), Protoparmelia is close to Miriquidica, from which it is distinguished mostly by ascus characters (non-amyloid tholus and different shape of the "masse axiale") reddish brown epihymenial pigmentation. The close relationship of the two genera is supported by the presence of otherwise rare, structurally similar secondary metabolites: lobaric acid in some Protoparmeliae and miriquidic acid in Miriquidicae. But the conidia of Protoparmelia are variable in shape, not always filiform and curved as in Miriquidica. The conidia of Protoparmelia are, however, variable in shape, not always filiform and curved as in Miriquidica. See also Hertel and Rambold (1987) for more information on the distinctions. Preliminary investigation of coastal populations of what was initially classified as Lecania reveals that undescribed species of Protoparmelia may be present, but the analysis is too premature to describe them at this time. |