FloraOfNewZealand-Mosses-38-Fife-2018-Mniaceae

The family Mniaceae and its allies have received much attention in recent decades from monographers, cytologists, and molecular systematists. Despite this attention, no consensus has arisen concerning the limits of this family; a narrow view is adopted here. The Mniaceae are represented in New Zealand by one widely distributed species, Plagiomnium novae-zealandiae Colenso, and one exceedingly poorly documented species known only from two sterile shoots from a high elevation site on Mt Ruapehu. Our widespread species is made distinctive regionally in part by its conspicuous plagiotropic and arching sterile shoots contrasting with erect and fertile shoots, its robust habit, and its large, broadly elliptic, singly costate, bordered leaves, which are strongly contorted when dry.Plagiomnium novae-zealandiae has been treated by many authors as conspecific with the northern hemisphere P. rostratum (Schrad.) T.J.Kop. The latter species is dioicous and lacks leaf decurrencies, while the N.Z. species is consistently synoicous and has clearly decurrent leaves on fertile plants. Plagiomnium novae-zealandiae is widespread on both main islands, occurring at the margins of streams, rivers, or lakes, as well as in wet sites on the forest floor, ranging from low elevation to nearly 1600 m a.s.l.; all occurrences from above 1000 m are associated with calcareous rocks.