Similarities in floral ontogeny and anatomy between the genera Francoa (Francoaceae) and Greyia (Greyiaceae)

A comparative study of the floral ontogeny and anatomy of Francoa, with one species, and Greyia, with three species, is made. Flowers arise nearly syn chronously on terminal raceme-like inflorescences with abortive growing tip . In Greyia, development of flowers shows a tendency toward monosymmetry, e xpressed in the initiation sequence of floral organs. Both genera are weakl y obdiplostemonous by a later displacement of antepetalous stamens ("second ary obdiplostemony"), and they develop a comparable semi-inferior, strongly grooved ovary with axile placentation. The staminodial nature of nectaries is rejected for both genera. The floral ontogenetic, anatomical, and morph ological similarities of the two genera are obvious and are consistent with the proposal for a close relationship between Greyia and Francoa supported by molecular data.