Pistillate and Staminate flower morphology and anatomy in dioecious Cordiera concolor (Gardenieae- Rubiaceae)

JUDKEVICH M.D; A. M. GONZALEZ

Salvador, Bahía

Conferencia; VI International Rubiaceae and Gentianales Conference.; 2014

The structure and anatomy of mature unisexual flowers of Cordiera concolor (Gardenieae- Rubiaceae) was investigated using scanning electron and light microscopy in order to determinate the organogenetic patterns in both unisexual flowers to contribute to the knowledge of the species. The results show that both types of flowers share: 1) a cupuliform calyx that externally has simple unicellular trichomes and paracytic stomatas, and internally, has 2-3 layers of dendroid colleters that secrete resine, 2) a nectary disc is located around the base of the style and having anomocytic nectarostomatas, 3) a 4-lobed corolla that externally has simple unicellular trichomes and paracytic stomatas, and 4) stamen fused to the corolla for a short staminal filament. The mesophyll in all floral pieces has cells with tannin and cells with druse. The pistillate flowers have an inferior ovary, bilocular with 2-10 ovules per locule. The style has two stigmatic branches, ovate and papillose. The anthers of pistillate flowers possess tetrads surrounded by callose, these tetrads collapse at maturity. The staminate flowers have an underdeveloped inferior ovary with two reduced locules and absent or rudimentary ovules, style with two long, spread stigmatic branches. The anthers in staminate flower produce pollen grains and have longitudinal dehiscence. Therefore, the flowers in this species are structurally perfect but functionally pistillate and staminate respectively.