Stem and leaf anatomy of six species of Verbena native to Buenos Aires province, Argentina

There are 21 species of Verbena L. in Argentina, six of which are found in the Buenos Aires province: Verbena gracilescens (Cham.) Verter; V. bonariensis L.; V. intermedia Gillies and Hook; V. litoralis Kunth; V. montevidensis Spreng. and V. rigida Spreng. These species are used in popular medicine for their hepatoprotective, digestive, anti-inflammatory, antidiarrheal and healing properties. The stems and leaves of these species were fixed and transverse sections were cut for observation with a light microscope in order to differentiate their anatomical features. Likewise a scanning electron microscope and an environmental scanning electron microscope were used to study the leaf surface of these species. The type and density of stomata and glandular and nonglandular trichomes were analysed in all species, as well as the internal structure of the leaf and stem. The Verbena species of Buenos Aires province have been characterized using these features to help in their identification.