Geitonogamy: a mechanism responsible for high selfing rates in borage (Borago officinalis L.)

Borage, a species traditionaly defined as allogamous, has revealed a high selfing rate although a mechanism of protandry has been confirmed in this plant. Studies investigating flower behaviour showed that several flowers open every day and that others are also receptive at the same time within a plant. Moreover, pollinator behaviour, mainly by bees, contributes to the selfing rate because it is demonstrated that these insects visit several flowers in a given plant before flying to other plants. The ecological studies reported here reveal the contribution of geitonogamous pollination to the high selfing rate detected in Borago officinalis L. Received: 23 March 2000 / Accepted: 26 May 2000