Floral Vascular System Anatomy of Heliconia rostrata(Heliconiaceae)

The floral vascular system of Heliconia rostrata Ruiz & Pavon were studied using paraffin section.Results showed that the carpellary dorsal bundles(cdbs)from the prolongation base were divided into two strands.A mixture of inner strands and placental bundles ran into the style.The two abaxial outer strands generated 2-4 branches and entered into the outer whorl at the two abaxial stamens,while the adaxial outer branch was the midrib of the staminode vasculature,which indicated its degenerate structure.After splitting into 3-5 strands at the top of the prolongation,the three parietal bundles(pbs)entered into the three stamens of the inner whorl and the remaining bundles of the ovary wall ultimately clustered into the perianth.Our results suggest that the degenerate structure with the outer androecial whorl is part of the androecium as it has the same origin of the vascular trace,Heliconiaceae is a sister family of the ginger group,different from the banana group.