Self-burial behaviour of Erodium cicutarium seeds.
(1) The self-planting mechanism of the hygroscopic 'seeds' of Erodium cicutarium was examined. (2) Burial depended first on the location of crevices by the seeds. (3) The seeds were more likely to establish themselves in large crevices, even when their awn-tails, awn-hairs and carpel-tips had been removed experimentally. (4) Once in a crevice, the probability of a seed remaining there and the depth attained were greater when the crevices were small. In small crevices, seeds with intact awns and carpels attained greater depths than that of those without these structures. (5) When crevices were small and common, the seeds became established after five uncoiling-recoiling cycles. In large crevices, eight cycles were required for establishment; when crevices were small and infrequent, forty cycles were required.