Different Patterns of Floral Ontogeny in Dimorphic Flowers of Pseudostellaria heterophylla (Caryophyllaceae)

Abstract

Pseudostellaria heterophylla, a cleistogamous species belonging to the Caryophyllaceae, was studied ontogenetically with SEM to investigate floral development in chasmogamous (CH) flowers and cleistogamous (CL) flowers. Comparative ontogenetic studies of this cleistogamous species revealed significant differences between CH and CL flowers. As opposed to other findings for cleistogamous species, the results of this study showed that divergence in the development of the floral forms occurs at inception, not later during organ growth. The floral organ inception in the CH flower is as follows: five sepal primordia are initiated in a helical sequence, 10 stamen primordia are initiated in two whorls (an antesepalous whorl and an antepetalous whorl sequentially), petal primordia are initiated by the division of common stamen-petal primordia, and three carpel primordia are initiated last. The floral organ inception in the CL flower is as follows: four sepal primordia are initiated in two pairs alternatively, two ...