Genecology ofAgrostis capillarisL. (Poaceae) — an invader into New Zealand: 1. Floral phenology

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Abstract
Agrostis capillaris has spread throughout New Zealand since its introduction 130 or more years ago. Genecological variation is investigated for clues to its success. Inflorescence number, time to 50% inflorescence emergence, time to 50% anthesis, and length of longest lamina and of longest stem were recorded for samples of 15 populations from a range of habitats in southern New Zealand, and for a collection from Campbell Island, grown together in a common garden in Dunedin. Differences between populations were not significantly related to major environmental trends, such as altitude and latitude; there was no evidence for the formation of ecotypes within the species. Populations collected from the same habitat type (e.g., alpine, or dry grassland) did not exhibit comparable floral behaviour. There were significant differences between some populations in the time to 50% completion of inflorescence emergence and anthesis, but no significant differences among populations in the time interval between the two floral events. Differences between genotypes within populations were of similar magnitude to those between populations. Maximum stem lengths differed significantly within but not between populations. The collection from Campbell Island had longer leaves and stems than those from mainland New Zealand, perhaps due to a different original seed source. Explanations for these results are discussed in terms of genetic divergence, plasticity, within-population variation, sampling methods, and non-linear adaptive trends.