Reproductive biology of leafy spurge (Euphorbia esula L.): Breeding system analysis

Leafy spurge (Euphorbia esula L.) represents a non-native, invasive weed that dominates many regions across North America. While many research efforts are aimed at controlling the growth and spread of this plant, relatively little is known about its breeding system. This study provides evidence that leafy spurge is self-compatible, with selfed plants producing roughly half as many seeds as outcrossed plants. Unpollinated flowers failed to set seed and thus preliminary tests for apomixis were negative. However, microscopic examination of pollinated flowers revealed that pollen robes did not appear to enter ovules in either selfed or outcrossed flowers. Therefore, leafy spurge exhibits structural evidence that suggests pseudogamy may play a role in the reproductive strategies of this invasive weed.