Apomixis in indigenous New Zealand woody seed plants and its ecological and wider significance: a working hypothesis

Evidence is presented for facultative apomictic seed formation in indigenous hardwood trees, shrubs and lianas in Riccarton Bush, Christchurch, and in indigenous woody species elsewhere in the New Zealand Botanical Region, including its offshore and outlying islands. For the most part, this evidence is based on the formation of abundant mature fruit in female plants isolated from pollen sources, and the subsequent germination of seeds and emergence of seedlings beneath these plants. In a few species, apomixy has been confirmed by cytological techniques. Sexual reproduction occurs in facultative apomicts and genetic diversity is maintained. Apomixis may be widespread among species central to the recovery and management of degraded forests and shrublands, and nationally threatened woody taxa with sparse, local, or restricted distributions. Unequivocal confirmation of the apomixis status hypothesised here and more information on the breeding systems of these species is needed if the extent and ecological role of the phenomenon in the New Zealand indigenous woody flora is to be understood.