Dicranaceae Schimp.

Plants highly variable in size, often robust, nearly always erect but rarely creeping (as in Sclerodontium), mostly forming tufts or turves. Stems simple or forked, with a central strand, usually tomentose. Leaves broadly to narrowly lanceolate, secund, spreading, or erect, sometimes sheathing below, mostly acute to acuminate at apices; mid and upper laminal cells variable in shape, smooth or less often papillose, often porose; cells of leaf base elongate; alar cells mostly differentiated. Costa single, narrow to very wide, ending near the apex or excurrent.

Setae elongate or rarely very short (as in Mesotus), straight or cygneous; capsules erect or inclined, stegocarpous; operculum mostly rostrate from a conic base. Peristome teeth16, flat, mostly divided c. halfway to base into segments of unequal width, usually vertically papillose-striolate below. Calyptra cucullate, smooth, entire or rarely fringed at base.

The Dicranaceae are a very large and taxonomically complex family of cosmopolitan distribution. Goffinet et al. (2009) included 41 genera in the family, while nine genera are accepted from N.Z. The largest genera worldwide are Campylopus, Dicranum, Dicranoloma, and Dicranella. Given its size and diversity the family is difficult to characterise. Campylopus and genera closely allied to it are often segregated in a subfamily Campylopodioideae (Frahm. et al. 1985). According to the introduction (authorship uncertain) to the family in the Mexican moss flora (Sharp et al. 1994, p. 111) "long, narrow, tapered leaves with a well-developed, single costa, differentiated alar cells, and flat, forked, vertically pitted-striolate peristome teeth" characterise most members of the family.

In the N.Z. species distribution summaries, Land Districts (L.D.) for which specific localities are not cited signify that the species under discussion has been documented from many sites (usually three or more). If more than three localities per L.D. are cited, the distribution within that L.D. is considered to be of particular interest, often because it constitutes a major proportion of the overall N.Z. distribution.

The following key includes genera (Leucobryum, Pseudephemerum, and Wilsoniella) that were placed by Sainsbury (1955a) in the Dicranaceae but placed in different families here.

Chorisodontium aciphyllum (Hook.f. & Wilson) Broth. This South American species was reported from N.Z. by Bartlett & Frahm (1983), based on two Denniston Plateau collections. On the strength of determinations by J.-P. Frahm and the subsequent joint report, C. aciphyllum was accepted for many years as part of the N.Z. flora. However, compared to the Bartlett Denniston Plateau collections, South American and South Shetland I. plants of C. aciphyllum (including the Hermite I. type in BM-Wilson!) are more robust, with leaves coarser in texture, longer (c. 7–9 mm), and not secund, and with costae much broader (mostly 250–350 µm in lower leaf). Also, in most, but not all, South American C. aciphyllum the abaxial surface cells of the costa at mid leaf (viewed in cross-section) are strongly and densely mamillose; such cells do not occur in the Bartlett collections. In my opinion, all records of C. aciphyllum from N.Z. are based on Bartlett misidentifications of aberrant and epilithic material of the usually epiphytic Holomitrium trichopodum and are discussed further under that species.

Leucobryum Hampe was treated as a member of the Dicranaceae by Sainsbury (1955) and by Scott & Stone (1976), but is here treated in the Leucobryaceae.

Pseudephemerum (Lindb.) I.Hagen was included in the Dicranaceae by Sainsbury (1955) but is placed in the Ditrichaceae in this work.

Trichodontium (Dixon) Fife is treated here as a taxonomic synonym of Kiaeria, as is its basionym Dicranum subgen. Trichodontium Dixon.

Wilsoniella Müll.Hal. was included in the Dicranaceae by Sainsbury (1955) but is placed in this work in the Ditrichaceae.