A new species of Coprosma Sect. Acerosae (Rubiaceae) endemic to the South and Stewart Islands of New Zealand

Abstract

A new endemic addition to Coprosma Sect. Acerosae, Coprosma elatirioides, is described from New Zealand. The new species is a common shrub of mid to oligotrophic wetland habitats along the West Coast and in the southern third of the South Island, and on Stewart Island. Previously, Coprosma elatirioides was included within a broad circumscription of C. brunnea, from which it is distinguished by its non‐flexuous branching habit, comparatively large, conspicuous and persistent calyces and a deeply divided corolla on female flowers, and restriction to wetland habitats. Coprosma elatirioides is most similar to C. inter‐texta, from which it is distinguished by its subscandent, trailing growth form, shortly sheathing and conspicuously denticulate stipules, fleshy coriaceous, adaxially pubescent leaves with obtuse apices, and ecology. C. elatirioides is further distinguished from C. brunnea, C. intertexta, and the other coprosma species of Sect. Acerosae by nrDNA internal transcribed spacer (ITS) and external transcribed spacer (ETS) sequence differences.