The morphology of styles and stigmas inVicia (Leguminosae), and its systematic implications

Abstract

The morphology and development of styles and stigmas ofVicia, one of the five genera of tribe Vicieae, were studied by scanning electron microscopy to contribute to a revision of infrageneric classification. Among the 22 species examined, variations were found as to: (1) whether a boundary between stigma and style is V-shaped when viewed from the adaxial side or not; (2) whether stylar hairs sprout on all sides of the style or only on the abaxial side; (3) whether a hairy area of the style connects with the stigma area first at lateral sides or at an adaxial side; (4) whether styles are tapered or bottle-neck-shaped; (5) whether styles are straight or bend abaxially. Based on these variations, five morphological types of styles and stigmas were provided with a diagnostic key. Comparisons with related tribes Cicereae, Coronilleae, Galegeae, Hedysareae, Loteae and Trifolieae as possible outgroups suggested that the V-shaped boundary between stigma and style is a synapomorphy of some species withinVicia, and that a dorsally compressed and abaxially tufted style, which was distributed in separate subgenera and sections sensu Kupicha but is now known to occur together with the V-shaped boundary, has evolved only one time in the genus, rather than more than once as supposed earlier.