English

Abstract

Dawson, J. W. (Botany Department, Victoria University of Wellington, Wellington, New Zealand) 1986. Floristic relationships of lowland rainforest phanerogams of New Zealand. Telopea 2(6): 681-695 Floristic relationships are examined for woody and epiphytic herbaceous genera of the New Zealand lowland rainforest. The 80 genera are divided into five categories: (I) gymnosperms; (2, 3, 4) non-endemic angiosperms; (5) endemic genera and genera of uncertain status. Climatic preference is the basis for division of the non-endemic genera: (2) lowland tropical; (3) lowland and montane tropical to Australian temperate; (4) montane tropical and lowland south temperate. The species of angiosperms are grouped into standard leaf-size classes. Patterns observed in correlations of leaf size, latitude and growth form are shown. Maps illustrate the Australasian distributions of the non-endemic genera; occurrences of New Zealand genera in South America, the Pacific and South Africa are noted. Comparisons among the non-endemic genera revealed the following trends: the number of species per genus is lowest in lowland tropical genera (1.4 per genus) and greatest in the montane tropical and south temperate (4.2 per genus); about one-third of the species in lowland tropical genera are microphyllous, in the other two categories about two-thirds of the species are microphyllous; lowland tropical genera (category 2) occur only in rainforest, of species in category 3, 28% occur also in non-forest habitats, and in category 4, 48%; 27% of species in category 2 belong to genera of probable southern origin, for category 4, 90% of species. Contrary to these trends is the greater frequency of specialized growth forms (lianes and epiphytes) in category 4 (36%) compared with 16% of species in category 2. A possible explanation for this trend is given.