Biological and anatomical characteristics of the rose-scented geranium (pelargonium graveolens,L'Hér.) grown in the south of Tunisia

Pelargonium graveolens,l'hér.,is among the most cultivated plants in tunisian gardens as ornamental species. although it is well known for its exceptional aroma and essential oils benefits,it is still unknown on the scale of its biological and anatomical characteristics. it is in this context that this study lies to account for the characterization of this species. in fact,the anatomical investigations showed that while the stomata density of this species was high particularly on the leaf underside (42.13 st/mm2),it was much lower (6.36 st/mm2) in the petiole. besides,the flowers are grouped into umbelform-cym inflorescence. furthermore,the observations of the fingerprints of different aerial organs using the light microscope have shown that all parts are covered with two types of hairs or trichomes (glandular and non-glandular). a high density of both hair types was recorded on the different tissues analyzed in this study with an outstanding superiority for the stems. the results of leaf analysis have also shown that chlorophyll a content is higher than the chlorophyll b one.