Development of keeled flowers A study using scanning electron
microscopy has revealed that the keeled petals of Leguminosae
and Polygalaceae are fundamentally different. 25 Mar 2011
Scanning electron micrographs of dissected floral buds of
Polygala violacea (left) and P. gomesiana (right) (Image: M.
Angélica Bello Gutierrez). In keeled flowers, one of the petals
(or two fused petals) forms a complex hooded structure that
encloses the reproductive organs. The keel can facilitate pollen
presentation in cases where pollen is deposited on it. Keeled
flowers are highly characteristic of some Leguminosae and
Polygalaceae, two of the four families that comprise the rosid
eudicot order Fabales. Research on floral development at Kew and
Reading University, conducted by former Kew PhD student Angélica
Bello, shows that the characteristic crest that occurs on the
keel of some Polygalaceae develops relatively late in floral
ontogeny. Despite some ontogenetic similarities, the
morphologies of the two types of keeled flowe