REPRODUCTIVE BIOLOGY OF AUSTRALIAN ACACIAS IN THE SOUTH-WESTERN CAPE PROVINCE, SOUTH AFRICA

Several Australian members of the genus Acacia L. have attained weed status in the Cape Province, South Africa. It is shown that in the Cape the plants are pollinated but lack effective seed predators. Mature plants drop seeds numbering usually in the range 1 100 to 7 000 m−2yr−1. They have a seed-bank in the soil about two to five times this magnitude, about 95 per cent of which is dormant. It appears that the decline of viability with age may be relatively very slow. These findings are shown to be critical in planning control-methods. (Miss S. J. Milton and Dr A. V. Hall, Bolus Herbarium, University of Cape Town.)