VEGETABLE POWDERS 



Scale in Microns. 



Fig. 137. MENTHA PIPERITA. 



. Upper epidermal cells. 



b. Lower epidermis. 



c. Trichomes, simple, showing cuticular markings (a medium sized trichome). 



d. Gland, top view. 



e. Small glandular trichome. 



27 



