Flaveria

Flaveria is a genus of plants in the marigold family. They are sometimes called yellowtops. Some are annual or perennial herbs and some are shrubs. They bear yellow flowers in heads, with zero, one, or two ray florets in each head. These plants are found in the Americas, Asia, Africa, and Australia. While some members of this genus use the more common C3 carbon fixation pathway, others are C4 plants, and some are intermediate. With closely related species exhibiting different forms of metabolism, Flaveria has been a model genus for studies on the evolution of photosynthesis. A monograph by A.M. Powell from 1978 is the most comprehensive study of morphology and biogeography for the Flaveria species to date. Molecular phylogenetic studies have clarified many of the evolutionary relationships between Flaveria species.