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African Olive, Olea europaea subsp. cuspidata (Wall. ex G.Don) Cif. (family Oleaceae) is a dense-crowned tree introduced into Australia for horticulture in the mid 19th century. In recent decades, African Olive has become an aggressive woody weed, capable of forming a dense and permanent canopy in a wide range of vegetation types in south-west Sydney and beyond. Characteristics of African Olive invasion in south-west Sydney, and its seed dispersal by frugivorous birds are consistent with experience from Norfolk Island and Hawaii. We use records and aerial photographs from Mount Annan Botanic Garden and other bushland areas in south-west Sydney to describe the invasion stages and impacts of African Olive. The capacity for African Olive to establish in both temperate and subtropical zones, underlie the potential for spread well beyond current distribution in New South Wales. Research is now required to further develop control techniques and ecological restoration strategies for areas of heavy African Olive infestation. Mapping of current locations and a coordinated control strategy for African Olive is required to prevent future permanent loss of native plant diversity.
Fresh seeds of the endangered Hakea dohertyi Haegi (Proteaceae) germinated at 15°C (with 12 hour light) within 14 days. At higher temperatures (20°, 25°C) seeds were slower to germinate. After 28 days only 5% of seeds germinated at 30°C, but when moved to 15°C, close to 100% of seeds germinated within 14 days. Having established optimum germination conditions, the effects of ex situ storage conditions and duration were examined. Storage at low moisture content appeared to have little effect on the germinability of Hakea dohertyi seeds and this species can be considered orthodox in that respect. Seeds stored at 4.5 or 9% moisture content, 5 or -20°C and tested after 1 and 7 years of storage achieved close to 100% germination. Issues relating to the in situ and ex situ conservation of Hakea dohertyi are discussed.