Patterning the floral meristem.

Flowers are reproductive structures unique to the angiosperms. Flowers, which develop from small mounds of cells called floral meristems, show a number of universal patterns such as the arrangement of organs of different type along thefloral axis. However, other conserved patterns, such as floral asymmetry, are merely conserved within different subgroups. This review discusses the emerging picture of early operating developmental mechanisms, which pattern floral meristems along the radial and dorsiventral axes, and of later-acting ones, which pattern tissue differentiation within floral organs.