Pollen Limitation in a Monocarpic Species, Ipomopsis Aggregata

(1) We tested whether seed production in the perennial monocarpic plant Ipomopsis aggregata (Polemoniaceae) was pollen-limited by adding outcross pollen to open stigmas of plants on three occasions at weekly intervals. We compared fruit set and seed set per fruit with a set of adjacent, untreated plants of the same average height and flower number. (2) Experimental pollination doubled the number of flowers producing seed after each occasion and increased the average seed set per fruit for the first one. (3) Plants treated with pollen showed correlations between seed production and height and aborted seed production consistent with resource limitation, but untreated, naturally pollinated plants did not.