Reproductive Ecology of Ocimum americanum L. and O. basilicum L. (Lamiaceae) in India

Abstract Ocimum americanum and O. basilicum bloom once a year. They produce flowers over a long period, a few flowers being produced each day. The flowers of both are short-lived (3-4 hours), bisexual, zygomorphic, and chasmogamic with anthers dehiscing in the bud stage. The open flowers offer nectar and pollen as rewards and are visited and sternotribically pollinated by day-flying animals. The blossoms are flag-shaped, and the reproductive organs are close to the lower corolla lip. The stamens and stigma show movements immediately after anthesis and remain for 20–30 minutes and this may cause self-pollination. Both species reproduce primarily through autogamy. Flowers are open during 5:30–13:30 hr in O. americanum and during 7:00–13:00 hr in O. basilicum . Certain bee species like Apis florea, A. cerana indica, Amegilla sp., and Pseudapis oxybeloies , and the butterfly Surandra queretroum are the most frequent and consistent visitors and can be pollinators for both plant species.