Environmental variation in the long term pattern of germination from hard seeds of Lupinus varius

Abstract

The long-term field germination pattern from hard seeds of sandplain lupin varied between sites. At Perth, where environmental conditions are almost ideal for the species, the hard seeds formed at the end of a growing season soften and germinate over the following five years. Some 15-20 per cent softened each summer and germinated with the following autumn rains. At Chapman, some 300 miles north of Perth in a drier more marginal environment for the species, all the hard seeds softened and germinated within two years. This wide site variation in the spread of germination from hard seeds is ascribed to environmental differences during the growing and dry seasons.