Some Malpighiaceae produce minute cleistogamous flowers in addition to showy chasmogamous flowers. Standard techniques fail to reveal how the cleistogamous flowers achieve self-fertilization. Fluorescence in longitudinal sections shows that the pollen germinates inside the indehiscent anther. The pollen tubes then grow down through the filament, into the receptacle, up into the carpels, and into the nucellar beak of the ovule.