Cleome is a genus of flowering plants in the familyCleomaceae, commonly known as spider flowers, spider plants, spider weeds, or bee plants. Previously, it had been placed in the family Capparaceae, until DNA studies found the Cleomaceae genera to be more closely related to the Brassicaceae than the Capparaceae. Cleome and clammyweed, (Polanisia dodecandra) can sometimes be confused. The simplest way to differentiate the two is to compare the seedpods which project out or down on cleome and up on clammyweed.
The genus contains species which show an evolutionary progression from C3 to C4 photosynthesis. This, combined with it being very close to the Brassicaceae with the model plant species Arabidopsis thaliana, makes it an ideal genus in which to study the evolution of C4 photosynthesis. Morphological differences that demonstrate the transition from C3 to C4 include C3 species having leaves with more veins and larger bundle sheath cells. Also, species such as Cleome gynandra produce proteins needed for C4 photosynthesis. Three species independently acquired the C4 pathway, while others are C3–C4 intermediate or C4-like.
^ abcHuxley, A., ed. (1992). New RHS Dictionary of Gardening 1: 652-653. Macmillan. ISBN1-56159-001-0.
^Marshall, D.M.; Muhaidat, R.; Brown, N.J.; Liu, Z.; Stanley, S.; Griffiths, H.; Sage, R.F.; Hibberd, J.M. (2007). "Cleome, a genus closely related to Arabidopsis, contains species spanning a developmental progression from C3 to C4 photosynthesis". The Plant Journal. 51 (5): 886–896. doi:10.1111/j.1365-313X.2007.03188.x. ISSN0960-7412.