LEAVES. 



57 



PLATE XXII. 



FIG. 32. Powdered Betony Leaves (x 



ei, Epidermis of under surface, smooth. 



en, Epidermis over the veins, striated. 



es, Epidermis of upper surface, smooth. 



ip, Scar of fallen hair. 



I, Bast. 



me, Mesophyll. 



pa, Palisade cells, surface view. 



p'a', Palisade cells, longitudinal section. 



pg, Glandular hairs with bicellular glands. 



p'fi'j Glandular hairs with quadricellular glands. 



pt, Simple hairs with thick walls, some entire, some broken. 



tf, Cortical tissvie of midrib. 



-ti, v, Vessels, &c. 



