Floral protogyny, self-compatibility and the pollination of Ourisia macrocarpa (Scrophulariaceae)

Abstract

The simple gullet flowers of Ourisia macrocarpa are borne in sequentially blooming whorls. They are pollinated primarily by small halictids and syrphids. The plants are self-compatible. Hemisynchronous, multi-cycle, incomplete proto-gyny allows both autogamous and geitonogamous selfing. Autogamy is infrequent due to movements of stamens and styles, and to allogamous pollination during the female stage. Minimum and maximum estimates of the frequency of geitonogamous pollinations are 2.4 and 31.2%. Avoidance of self-pollination is probably the most important selective force that has favoured floral protogyny.

Keywords:

• Ourisia macrocarpa
• Scrophulariaceae
• New Zealand
• pollination
• protogyny
• autogamy
• geitonogamy
• self-compatibility
• floral despecialisation