Achyranthes aspera (Amaranthaceae) a new indigenous addition to the flora of the Kermadec Islands group

Abstract

Achyranthes aspera (Amaranthaceae) is reported from Macauley Island, the largest of the five main islands comprising the southern group of the Kermadec Islands. Because Macauley Island is remote and difficult to access, we consider it very unlikely that A. aspera was introduced to the island by humans. It is suggested that the species colonised Macauley Island naturally via an avian vector, from seeds dispersed by sea birds travelling between the Norfolk Island group and Macauley Island. Although A. aspera has hitherto been considered a naturalised species in the New Zealand Botanical Region, we suggest that the Macauley occurrence should be regarded as a recent native addition to the flora of the Kermadec Islands. The species has been assessed with the Conservation Status of “Coloniser” using the New Zealand Threatened Species Classification System.