ANATOMICAL AND MORFOPALINOLOGICAL CHARACTERS FOR THE DETERMINATION OF Plectranthus coleoides Benth. c.v. mintleaf (LAMIACEAE)

Abstract

Plectranthus coleoides c.v. mint leaf (vaporub) is an exotic ornamental plant which is used in folk medicine to solve respiratory problems. The vegetative part is sold in the markets of Mexico, because flowering is very frequent. The distinctive feature of the genus Plectranthus is the flower with four lobes on the upper lip and one at the bottom. The taxonomic determination can not only rely on floral morphology since characters are unstable and connect with intermediate forms, so an anatomical study at the root, stem and leaf, as well as the morphology of the pollen will help to a more precise identification. A crossed-section dissection -to describe anatomical characteristics- was practiced to individuals from four entities. The observed similarities are as follows: epidermis of root, a one layer with trichome stem and leaf not glandular uniseriated, glandular trichomes capitated like and diacític stomata on both surfaces. On stem, the collenchyma is subepidermic, angular like form in discontinuous bands. From the samples that flourished, morphological description of pollen was done. The grains are hexacolpate, with varicose ornamentation and spheroidal form to suprolate. Finally, quantitative data with a test of significance were valued to obtain similarities and differences of the anatomical features of all the studied individuals. There was little variability, so it can be concluded that the material belongs to the same species.