Seeds are oval and flat, and although the pollination process has not been studied, seed dispersal seems to be profuse since populations can achieve high density in localized areas, especially along rivers. Harperella tolerates - and may need - a very specific water regime, which includes moderately intensive spring floods. After floodwaters recede, seeds germinate in shallow rocky crevices and complete their life cycle with root systems that are submerged or saturated.