Enchylium (Ach.) Gray
Nat. Arr. Brit. Pl., 1: 396, 1821 - Collema sect. Enchylium Ach., Lichenogr. Univ.: 629, 1810.
Systematics:
Phylum: Ascomycota Caval.-Sm.
Subphylum: Pezizomycotina O.E.Erikss. & Winka
Class: Lecanoromycetes O.E.Erikss. & Winka
Subclass: Lecanoromycetidae P.M.Kirk, P.F.Cannon, J.C.David & Stalpers ex Miądl., Lutzoni & Lumbsch
Order: Peltigerales Walt.Watson
Suborder: Collematineae Miądl. & Lutzoni
Family: Collemataceae Zenker
Brief description: Thallus foliose to subsquamulose, homoiomerous, gelatinous and strongly swelling when wet, dark olive-green to black, ecorticate, attached by white hapters. Apothecia lecanorine, with a red brown disc and a usually persistent thalline margin. Proper exciple euthyplectenchymatous (rarely subparaplectenchymatous with elongated cells); epithecium brownish; hymenium colourless, I+ blue; paraphyses simple or sparingly branched, the apical cells clavate to subglobose; hypothecium colourless to yellowish, I+ blue. Asci (2-4)-8-spored, narrowly clavate to subcylindrical, the apex strongly thickened, the apical dome K/I+ pale blue, with a downwardly projecting K/I+ deep blue tubular structure. Ascospores 2-4-septate or submuriform, hyaline, ellipsoid to fusiform. Pycnidia common, laminal or marginal globose, paler than thallus. Conidia bacilliform, slightly swollen at both ends. Photobiont cyanobacterial (Nostoc, the cells in long chains). Chemistry: without lichen substances.
Note: A molecular study of the Collemataceae genera Collema s.lat. and Leptogium s.lat. by Otálora & al. (2014) has led to their re-circumscription, with two new genera and six old generic names resurrected, among which the genus Enchylium, to accommodate the Collema tenax-group (Degelius 1954), characterised by swollen and plicate thallus lobes, and apothecia that usually have a distinctly euthyplectenchymatous proper exciple. Most of the 9 species are saxicolous or terricolous; the two epiphytic species (E. conglomeratum and E. ligerinum) were not included in the analysis of Otálora & al. (2014).
Type: Enchylium tenax (Sw.) Gray
