Floral Development of Three Maesa Species, with Special Emphasis on the Position of the Genus within Primulales

Floral development of three Maesa Forssk. species, M. argentea Wall., M. japonica(Thunb.) Moritzi ex Zoll. and M. perlarius(Lour.) Merr., was studied with a scanning electron microscope. The distinctive floral features of the genus, such as presence of two persistent bracteoles, perigynous flowers and many-seeded fruits, have been used to discuss the systematic position of the genus within Primulales. In addition, the development of common stamen-petal primordia, the number, arrangement and position of ovules and the shape of the anthers provide evidence in favour of placing Maesa in a separate family, Maesaceae, as suggested by Anderberg and Ståhl (Canadian Journal of Botany, 73: 1699–1730, 1995).