CISTACEAE - A PLANT FAMILY WITH HARD SEEDS

An examination of 203 seed lots from 42 Old World species (or 54 taxa) , with representatives from all five genera (Cistus, Fumana, Halimium Helianthemum, and Tuberaria) and an additional seed lot of the New Wor ld Lechea maritima shows that the phenomenon of hardseededness is a pr ominent characteristic of the entire Cistaceae family. Promotion of se ed germination in the laboratory can be obtained by mechanical scarifi cation and thermal pretreatment, while light seems to be totally ineff ective. A seed ecology syndrome for Cistaceae is postulated, featuring small seed size, hardcoatedness (primary dormancy), short-distance di spersal, long-term persistence in soil seed banks, fire- or heat-induc ed seed ''softening'', an opportunistic strategy of germination (germi nation at a wide range of temperature and light conditions), and a slo w germination rate of ''softened'' seeds. This syndrome is suggested t o endow Cistaceae, a principally Mediterranean family, with a consider able ecological advantage in the summer-dry and fire-prone Mediterrane an climatic conditions.