Novel self-pollination mechanism in Roscoea

Delayed selfing is the predominant mode of autonomous self-pollination in flowering plants. Fan and Li investigate the characteristics of reproductive ecology of Roscoea debilis (Zingiberaceae) and report a novel delayed-selfing mechanism in this ginger. They find that stigmatic fluid forms a globule on the stigma late in the anthesis. This enlarges and seeps onto nearby pollen grains after the flower has wilted, and induces germination and elongation of pollen tubes towards the stigma. Visits by effective pollinators are rare in natural populations, so they conclude that R. debilis relies primarily on this delayed-selfing mechanism for reproduction.