Cardamine lacustris, a new combination for Iti lacustris (Brassicaceae)

Abstract

Artificial hybrids between Iti lacustris and a New Zealand species of Cardamine are easily produced and highly fertile. The hybrids are intermediate between Cardamine and Iti in leaf characters, but are more like the Cardamine in their perennial growth habit, floral characters, and explosively dehiscent siliques with recoiling valves. These fertile hybrids and previously published molecular data imply that Iti and Cardamine are very closely related and should be considered congeneric. A new combination, Cardamine lacustris, is provided for Iti lacustris. A combination of flower and silique characters of C. lacustris, including only four stamens, short‐oblong siliques, passive dehiscence, and non‐recoiling valves, make this a particularly unusual and interesting species of Cardamine.