Cytotaxonomy of the large Asteliads (Liliaceae) of the North Island of New Zealand

Abstract

Five species of Astelia, as defined by Skottsberg in 1934, and two species of Collospermum were studied. Results show that the present names do not adequately reflect relationships, but, since the nomenclatural problems extend beyond the group of species studied, names as defined by Skottsberg are retained. In section Desmoneuron, A. trinervia is hexaploid and stands apart from the diploid A. solanderi in some morphological characters and also in ecological tolerances. Two subspecies of A. solanderi are recognised on the basis of morphological and phenological criteria. Natural hybrids are recognised between A. solanderi and A. banksii, the latter a diploid species of section Isoneuron. This indicates a genetical relationship between two sections which had, on morphological grounds, been placed in separate subgenera. In section Tricella, A. nervosa, A. nervosa var. silvestris, and A. cockaynei form a polyploid series, and they differ ecologically as well as in some morphological characters. They should be treated as three separate species. Collospermum differs from Astelia in a number of morphological features. Chromosome numbers are similar, however, and phenological patterns follow the same general outlines, indicating close relationship.