Verbena Incompta P.W.Michael: an overlooked name for an old weed in New Zealand

ABSTRACT Verbena incompta, an apparent native of South America, has been a misunderstood weed in New Zealand. Verbena incompta had been confused as intermediate between V. bonariensis and V. brasiliensis in Australia and Europe. Now Verbena incompta is known as a distinct species, being named in 1995. Until recently, this plant was mistaken for V. bonariensis in New Zealand, where it is widespread, found from the north of the North Island to the north of the South Island. Verbena incompta is a more robust plant then the rarer V. bonariensis, and these species can be easily separated: V. incompta has elongated flower spikes and V. bonariensis a broader corolla. The presence and history of the V. incompta in New Zealand is discussed with notes on its distribution and invasiveness since its naturalisation in 1871. The three species in the Verbena bonariensis complex (V. incompta and V. brasiliensis being the other two species) are compared and discussed with particular attention paid to distinguishing V. incompta and V. bonariensis. This was done through review of the overseas literature, and the examination and reidentification of herbarium material of Verbena in New Zealand. This showed that V. incompta is the most common weedy species of the Verbena bonariensis complex collected in New Zealand.