Fig. 5. Leaf ultrastructure of senna. A, scanning electron micrograph of a cross-section of a senna leaflet. AB, abaxial; AD, adaxial; arrowhead, minor vein; BE, bundle sheath extension; M, mid vein; P, palisade mesophyll; T, trichome. Scale bar = 150 µm. B, epicuticular crystalline wax. Scale bar = 3.3 µm. C, close-up of a trichome surface showing micropapillate sculpturing. Scale bar = 7.5 µm.