In a clear example of floral 'behavior,' flowers in at least 80 angiosperm flowers undergo dramatic, often localized color changes that provide signals for a broad range of pollinators (Weiss 1991,1995; Weiss and Lamont 1997). Floral color change is a two-part system: 1) plants retain older flowers and the resulting large display attracts pollinators from a distance; 2) floral color phase directs pollinators to rewarding and sexually viable flowers at close range (Weiss 1991). Both plant and pollinator benefit: the plant receives efficient pollination service, and the pollinator is accurately directed to a source of nectar or pollen.

Maryam Farzad (co-mentored by Martha Weiss and Heidi Elmendorf) recently completed her dissertation on the biochemical and molecular bases of floral color change in Viola cornuta, in collaboration with molecular biologists at Georgetown and at the USDA in Beltsville, MD (Farzad et al. 2001). Chris Drummond, a graduate student in Matt Hamilton's lab, is using quantitative and molecular genetic tools to investigate the evolution of floral color change in lupines.