Neckera is a genus of 71 species (Crosby et al. 2000) found throughout the world. It has been re-gionally revised for many areas—eastern North America (Crum & Anderson 1981), Pacific North-west (Lawton 1971), Mexico (Smith 1994), Neotropics (Sastre 1987), Great Britain (Smith 2004), Belarus (Rykovsky & Maslovksy 2004), Middle Russia (Ignatov & Ignatova 2003), Karelia (Abramov & Volkova 1998), Japan (Noguchi 1989), tropical Africa (De Sloover 1977), South Africa (Magill & Rooy 1998), eastern India (Gangulee 1976), Tibet (Li 1985), southern Australia (Scott & Stone 1976), and New Zealand (Beever et al. 1992)—and as a result 42 of the species are well known. Brotherus (1925) provided the last comprehensive treatment of Neckera.

The genus is found predominantly as an epiphyte, but it also occurs on rocks and boulders. In Central America it is found only at high elevations. Gametophytically, Neckera is characterized by its often pendent habit and complanate-foliate stems that lack a central strand. The presence or absence of paraphyllia is a widely variable feature of Neckera. In some species they are abundantly present, in others apparently absent, and in still others at times either present or absent. The relative abundance of paraphyllia is also a variable feature in many Neckera species, and the presence of paraphyllia in some species appears to be correlated with the presence of perichaetia and to a lesser degree perigo-nia. The leaves in Neckera areusuallyoblong-lanceolate or ovate-lanceolate, asymmetric, acute to ob-tuse, and with the margins broadly inflexed on one side below. Its leaf cells are smooth and rhombic to fusiform at the apex. Although many Neckera species have undulate leaves, there a number of spe-cies with plane leaves. The costae in Neckera are considerably variable between species; some char-acteristically have short, faint, double costae, while in others they are long and single. While the ca-lyptrae in Neckera are typically cucullate, at times they are mitrate. The capsules of Neckera can be immersed or exserted, they are erect, cylindric, and they have weakly developed annuli. Stomata can be present or absent. The genus has a neckeroid peristome: narrow exostome teeth that are typically cross-striate at the very base on the dorsal surface and an endostome with low basal membranes, nar-row, perforate, but not keeled segments, and cilia absent to rudimentary. Enroth (1994b) regarded the Neckera gametophyte and sporophyte to be evolutionarily advanced within the Neckeraceae.

The name Neckera was given in honor of Noël Martin Joseph de Necker (25 December 1730–1793), a French-born botanist and bryologist. He later was “kurpfalzischer Botaniker” at Mannheim (Stafleu & Cowan 1981; Frahm & Eggers 2001). Necker was an opponent of Hedwig’s views on the sexuality of mosses (Crum & Anderson 1981).