title: Plant size, geitonogamy and seed set in Ipomopsis aggregata.
abstract: We used powdered fluorescent dyes to estimate receipt of self vs. outcross pollen in the self-incompatible species Ipomopsis aggregata (Polemoniaceae). Flowers on small and large plants received equal amounts of outcross pollen, whereas flowers on large plants received more self pollen, so the proportion of self pollen delivered through geitonogamy increased with plant size. In natural populations emasculation of all flowers on a plant raised average seed set per flower from 5.19 to 6.99 and also raised fruit set, though not significantly. From these results one expects a negative correlation between plant size and seeds per flower. The opposite trend was observed in a sample of plants in the field, suggesting that deleterious effects of geitonogamy on female fecundity in large plants can be overruled by other factors such as size-related fruit or seed abortion. Results are discussed in relation to the evolution of gynodioecy.
authors.affiliation: Department of Population Biology, University of Leiden, P.O. Box 9516, 2300 RA, Leiden, The Netherlands.|Rocky Mountain Biological Laboratory, 81224, Crested Butte, CO, USA.
authors.forename: Tom J
authors.initials: TJ
authors.lastname: de Jong
authors.affiliation: Department of Biology, University of California, 92521, Riverside, CA, USA.|Rocky Mountain Biological Laboratory, 81224, Crested Butte, CO, USA.
authors.forename: Nickolas M
authors.initials: NM
authors.lastname: Waser
authors.affiliation: Department of Biology, University of California, 92521, Riverside, CA, USA.|Rocky Mountain Biological Laboratory, 81224, Crested Butte, CO, USA.
authors.forename: Mary V
authors.initials: MV
authors.lastname: Price
authors.affiliation: Earlham College, Box 1198, 47374, Richmond, IN, USA.|Rocky Mountain Biological Laboratory, 81224, Crested Butte, CO, USA.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Ring
keywords: Evolutionary ecology; Monocarpic perennial; Pollen transfer; Self-incompatibility