| Summary: | Observations on the phenology, breeding systems, seed germination and vegetative reproduction of 10 widespread and abundant species of flowering plants on the isolated subantarctic Macquarie Island were made over three field seasons. The reproductive behaviour of these species fall into four main patterns. Small herbs and grasses such as Montia fontana and Poa annua exhibited traits suitable to colonizing bare ground including selfing capabilities and in general, rapid phenology. Medium herbs and medium to large grasses, major contributors to biomass on the island (including the large tussock grass Poa foliosa), were capable of juvenile vegetative expansion, had slow phenologies and high seed germinability. The two large herb species on the island, Stilbocarpa polaris and Pleurophyllum hookeri can be described as perennial stayers. Both possess extensive storage tissue and vegetative growth, have slow to very slow phenologies and low seed germinability. The major cushion plant species on the island, Azorella macquariensis does not appear to have any form of vegetative reproduction and has very slow phenology including overwintering buds. This species is a colonizer and tolerator of extreme conditions on the island. Environmental conditions likely to affect flowering plant reproduction on Macquarie Island are compared with those in arctic and alpine environments.
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