As clonal plants get larger, individual flowers become more surrounded by other flowers borne on the same clone. With very restricted movement of pollen reported for both animal- and wind-pollinated species, the breeding system may change as a consequence of a clonal plant covering greater amounts of space. In Carex platyphylla, a wind-pollinated, self-compatible sedge, the absolute and relative amount of endogenous pollen per flowering culm increases sharply as a plant grows from one to about 10 culms, then increases at a slower rate, given a constant rain of exogenous pollen. In Trifolium repens, a bee-pollinated, self-incompatible, stoloniferous clover, a model based on known patterns of flower placement and stolon growth patterns, coupled with estimates of pollen-deposition and floret-visitation patterns by bees, suggests that the number and length of stolon internodes affect successful pollination. Also, the distribution of seeds among inflorescences is affected by clonal growth patterns and bee beha...