Contribution of micromorphology to the taxonomy of Abrus (Leguminosae–Papilionoideae)

Despite the various taxonomic revisions of Abrus Adans., species and infraspecific delimitation are not always clear. In those revisions very little reference is made to micromorphological characters, in particular to those of the compound leaves, in spite of the stability of some of those characters. By using techniques of light and scanning microscopy this study reveals some interesting results concerning to leaflet surface, such as some of the characters of the epidermis cells, stomata, presence of papillae and trichomes. These characters show some range of variation at the species level but not at the subspecies level. We conclude that those structures can provide additional characters useful in Abrus for species and infraspecific segregation. This study also supports Breteler’s delimitation of the African Abrus species.