In order to establish rigorous quality control standards for plant drugs, in addition to active substances detection and use of classical microscopical methods, the morpho-anatomical changes caused by the environment must be considered, specially when the plant drug are leaves. In this study, leaves of Bouchea fluminensis cultivated in full sun or in shade were analyzed. Sun leaves are smaller than shade leaves, and their blades are more undulating and leathery to the touch. Anatomical analysis revealed a thick striated cuticle with anomocytic stomates on both faces, although few stomates were present on the adaxial face of shade leaves. Two types of hair were observed, one is a simple tector with ornamented walls, and the other is glandular, as well as collateral vascular sheafs without sclerified tissues, the smaller ones surrounded by a sheath of unsclerified cells. The mean thickness of the mesophyll and the height of the palisade parenchyma cells of sun leaves are significantly higher than in shade leaves, which allows them to be easily distinguished. Failure to observe these photomorphogenic changes in plant species may give misleading results in the identification of plant drugs.
Bouchea fluminensis; Verbenaceae; morpho-anatomy; quality control