PLATE IV. 



Fig. 7. Cross section of leaf through the midrib. X 300. e, Epider- 

 mis, showing cuticle; /', photosynthetic cells; g, midrib; h, resin duct; i, 

 water-storage cells. 



Fig. 8. Longitudinal section of resin duct. X 500. j, Starch sheath ; 

 k, cells of resin duct; /, collenchyma. 



Fig. 9. Cross section of resin duct. X 500. in, Resin duct; n, bast; o, 

 starch sheath; p, collenchyma. 



Fig. 10. Tangential section of leaf. X 500. q, Photosynthetic tissue; 

 r, veins; s, water-storage cells. 



