Recovery of a sexual and an apomictic hybrid from crosses between the facultative apomicts Hieracium caespitosum and H. praealtum

Hybridisation is a rare event in facultatively apomictic species. We report the recovery of two hybrids from reciprocal crosses between the facultatively apomictic species Hieracium praealtum and H. caespitosum. Both parents were tetraploid (2n=4x=36). H. caespitosum x H. praealtum (CR6) was a hexaploid (2n=6x=54) and an apomict. The increased ploidy number is evidence of a BIII hybrid origin, having arisen from the fusion of a reduced and an unreduced gamete. In contrast, the hybrid recovered from the reciprocal cross H. praealtum x H.

Divaricating shrubs in Patagonia and New Zealand

There are at least three hypotheses to account for the abundance of divaricating shrubs in New Zealand: 1) Ratites in the form of 11 species of moa, led to divarication for browse protection (Greenwood and Atkinson, 1977); 2) Divarication evolved as a microclimatic shield (McGlone and Webb, 1981); 3) Divarication evolved to aid leaves in light harvesting (Kelly, 1994). In Patagonia before human arrival, there were browsing mammals in addition to the ratite rhea.

Light conditions and the evolution of heteroblasty (and the divaricate form) in New Zealand

Heteroblasty, changes in vegetative phenotype during ontogeny, is unusually common in the New Zealand flora. Some feature(s) unique to the New Zealand situation must have influenced the evolution of this strategy. Similarities were examined between the ontogenetic changes in phenotype and growth strategy in Elaeocarpus hookerianus, Carpodetus serratus and Pseudopanax crassifolius. Variation in hypothesised light capture efficiency of juvenile and adult forms can be related to changes in the light environment that these growth forms experience.

The genetics of naturalization: A comparison of morphological variation within and between populations of Agrostis capillaris L as an exotic in New Zealand and as a native in Britain

Previous work in New Zealand has shewn that genetic variation within populations of Agrostis capillaris can be comparable to that between populations, even between populations over a very wide environmental range. To determine whether this reflects the recent advent of A. capillaris in New Zealand, with a small founding gene pool and a short time for ecotypic differentiation, populations from a comparable range of environments were sampled randomly in the same way in Britain.

Vegetation Texture as an Approach to Community Structure—Community-Level Convergence in a New Zealand Temperate Rain-Forest

Functional convergence of different communities in similar environments would be expected as an outcome of the operation of 'assembly rules'. At an ecological level, competitive exclusion would restrict the co-occurrence of species with similar niches. Repetition of competitive sorting on an evolutionary time scale might lead to character displacement.