Abstract: Scutellaria agrestis
A. St.-Hil. ex Benth.,
Lamiaceae (trevo-roxo) is cultivated
for medicinal purposes by residents of the riverine communities in the State of Amazonas,
Brazil. This study aimed to characterize the anatomy and to make histochemical analysis
on vegetative organs of S. agrestis. Samples of the leaf, stem and root were collected
from fi ve plants cultivated by the communities located in the Solimões river, Amazon.
These samples were fi xed and prepared following standard techniques for scanning
electron microscopy and for light microscopy. Histochemical tests were carried out on
sections to detect the main classes of compounds present in the secretion. Numerous
glandular trichomes are seen in both leaf and stem of S. agrestis. The leaves are amphihypostomatics
and show dorsiventral mesophyll. Hydathodes are present at the tip of the
marginal teeth. Anthocyanin pigments occur into the epidermal cells of the stem, petiole,
and abaxial leaf surface. The petiole is concave-convex shaped and bears collateral
vascular bundles. The stem showed square-shaped, evident endoderm, collateral vascular
bundles and parenchymatous pith. The root displays a typical protostelic structure.
Idioblasts containing mucilage and phenolic compounds occur in the cortex. These data
are important, as they can be useful to identify this species, contributing to the quality control of the medicinal plant.