MENTHA PIPERITA. PEPPERMINT. 



197 



long and many celled, the walls being marked with fine 

 longitudinal striae. These simple multicellular hairs 

 are non-glandular. They may contain chlorophyll grains 

 or tmorganized contents. Small glandular hairs are 

 also present. These are composed usually of two cells, 



Fig. 52. — Mentha Piperita in Powder. 

 Epi, Epidermis, above, of upper side; below, underneath showing 

 the pitted parenchyma; Tr, hairs or trichomes; Col, collenchyma; 

 P, pollen grains from flower; Ep, cross-section of epidermis showing 

 palisade cells; Fibr, fibres from midrib. 



a small quadrangular basal cell and an enlarged pyriform 

 apical cell. 



The oil glands are characteristic ; they are globose and 

 slightly flattened, multicellular with a short basal pedicel, 

 and filled with oil, in which, at times, crystals of menthol 

 may be present. Their walls are thin, but resistant to 

 evaporation. 



Ducts are not common in the powder ; they are usually 



