Mielichhoferiaceae Schimp.

Plants erect, small to medium-sized, dull or lustrous, variably coloured. Stems mostly simple, sometimes branched, often with subfloral innovations, in cross-section with a central strand present or rarely absent. Leaves uniform or rarely dimorphic, crowded near the shoot apex or evenly spaced, mostly erect or erect-spreading when moist, ovate-lanceolate, narrowly lanceolate, to broadly elliptic, sometimes bordered, toothed or rarely entire; upper laminal cells linear to rhombic, thick- or thin-walled, smooth, becoming shorter and laxer towards the insertion. Costa single, mostly thin, variable in length. Axillary gemmae sometimes present (in Pohlia) or absent.

Dioicous, paroicous or rarely autoicous. Perichaetia terminal or occasionally basal, often conspicuous and subtended by innovations. Setae usually single, elongate, flexuose; capsule stance variable, pendent to erect, cylindric to pyriform to short-ovoid, with a long or short neck that is sometimes longer than the urn; annulus mostly present and revoluble; operculum conic, sometimes ± apiculate or rostrate; stomata superficial or immersed. Peristome mostly double and well-developed, sometimes greatly reduced (as in Mielichhoferia). Calyptra cucullate, smooth. Spores spherical, smooth or papillose.

The genera Pohlia, Epipterygium, and Mielichhoferia are placed here in the Mielichhoferiaceae. This disregards an earlier stated intention (Fife 2015, p. 9) to treat these genera in the Mniaceae (q.v.). Their segregation from both the Mniaceae and the Bryaceae mirrors Shaw & Ramsay (2013), who were influenced by chloroplast DNA sequences published by Cox & Hedderson (2003).The genus Ochiobryum is also placed here on the strength of morphological evidence. Pohlia is represented in N.Z. by nine species, while each of the remaining three genera have only one regional species each.

Spence & Ramsay (2006, p. 320) retained Ochiobryum in their Australian treatment of the Bryaceae, opining that it appeared to be related to Pohlia and Plagiobryum (and, less plausibly, to Leptobryum). Previously published chloroplast genome molecular data presented by Cox & Hedderson (2003) show O. blandum (as Bryum blandum) embedded in their most likely tree (fig. 2) in a clade that includes the type of Bryum (B. argenteum). Their fig. 2 suggests an unresolved relationship to the northern hemisphere taxa Bryum muehlenbeckii and B. alpinum.

In their influential classification, Goffinet et al. (2009) accepted Ochiobryum and placed it in the family Mniaceae, a decision that I (Fife 2015) have previously accepted. However, on further reflection, the genera that Goffinet et al. placed in the Mniaceae, when viewed in a N.Z. context, seem a highly unnatural assemblage. It seems preferable to further restrict the Mniaceae and to place Mielichhoferia, Pohlia, and Epipterygium in the Mielichhoferiaceae, together with Ochiobryum. This partially conforms with Shaw & Ramsay’s (2013) Australian treatment.

The placement of Ochiobryum in the Mielichhoferiaceae is a tentative solution, based in part on its upper laminal cells narrowly hexagonal or rhomboid, thin-walled, becoming longer in the lower leaf, its weakly developed border, and axillary perichaetia usually restricted to the plant base.