Pollen grains may be small but they have a big job. Delivering a sperm to an egg is a little more complicated when the parents don't move around.

For plants, pollen success means reaching a receptive stigma, germinating and growing a pollen tube into the ovary, locating an ovule and only then entering and delivering a sperm to a receptive egg. Despite the importance of these events to plant reproduction, pollen performance is relatively understudied.

To address that gap, UC Santa Barbara botanist Susan Mazer and her colleague Joe Williams of the University of Tennessee organized a symposium at Botany 2014 that has now culminated in a special issue of the American Journal of Botany titled "The Ecology and Evolution of Pollen Performance."