Plagianthus regiussubsp.chathamicus(Malvaceae)— a new combination for a Chatham Islands endemic tree

Abstract

A new combination, at the rank of subspecies, is made for the Chatham Islands endemic lace bark, a tree previously known as either Plagianthus chathamicus Cockayne or P. betulinus var. chathamicus (Cockayne) Cockayne. Specific status is not warranted, the only consistent difference between Chatham Islands and New Zealand populations being that Chatham plants consistently lack a filiramulate, divaricating seedling to sub-adult phase. As an allopatric, insular race of P. regius, subspecies rank is preferred over that of variety or forma.

Phylogeny and Character Evolution in the New Zealand Endemic Genus Plagianthus (Malveae, Malvaceae)

“…2 ), whereas ssp. chathamicus is restricted to the Chatham Islands, a small isolated archipelago approximately 800 km east of the South Island ( Mueller 1864 ;de Lange 2008 ). Plagianthus regius ssp.…”

“…chathamicus differs from ssp. regius by the lack of a divaricating juvenile phase ( de Lange 2008 ;Burns and Dawson 2009 ). Lloyd (1985) proposed that nonrandom dispersal and establishment of plants with different characters was a form of species selection brought about by differential rates of migration, persistence, and speciation in island plants.…”