Morphology and vascular anatomy of the flower of Aconitum lasiocarpum (Rchb.) Gáyer subsp. Lasiocarpum (Ranunculaceae Juss.)

Abstract

The results of detailed investigation on morphological and anatomical organization of flower of Aconitum lasiocarpum (Rchb.) Gáyer are presented. It was established that current species has common features of the structure with other representatives from the genus Aconitum L. However, it differs by the shape and the size of the helmet, the number and the type of pubescence of the carpels, as well as the character of pubescence of the tepals, pedicels and bracteoles. It was shown that the tepals have trilacunar three-traced vascularization, while the filaments and nectaries – unilacunar one-traced vascularization. Similar types of innervation of stamens and nectaries (probably of staminodial origin). Suggest its common morphogenesis and homeotic origin. Since in the case of homoplasy, stamens and nectaries are unlikely to have the same organization of its vascular system which is functionally unjustified in the case of nectaries. Each of the carpels has three main vascular bundles (one dorsal and two ventral) which produce branched system of anastamoses and together supply the ovules. The special feature of gynoecium innervation is a fusion of the ventral ribs of adjoining carpels in the receptacle. These data are the basis for next comparative morphological and phylogenetic study which could be applied for verification and support of current hypotheses of evolution of a ranunculaceous flower.

Keywords

• aconitum
• floral morphology
• vascular anatomy
• nectaries