XVI International Botanical Congess

Flowers of extant basal angiosperms (Magnoliidae), are primarily bisexual with numerous spirally arranged parts. Breeding systems are characterized by protogyny, strong floral odors, movements of floral parts and in a number of taxa by thermogenic flowers. The pollinators are mainly beetles and flies. The recent discovery of thermoregulating flowers in Magnoliaceae and Illiciaceae suggests that heat is a key component in the pollination syndrome of Magnoliidae. Temperatures in many thermogenic flowers are in the range preferred by beetles. Heat production and fragrance may have been key components in attracting insects in early plants. Fragrance could signal not only food and mating sites but also heat (a resource).