,' / 

 PLATE XXXVir"^ 



(No. 15.) 



Fig. 1. Cross section of old stem. X 17%. a., collenchyma rib; ft, cal- 

 cium oxalate crystals; c. palisade parenchyma cells; rf, tracheal tubes; 

 e, phloem masses surrounded by xylem; /', calcium oxolate crystals. 



Fig. 2. Cross section of young stem, x 34. a, short chloroplast-bear- 

 ing cells; b, secondary xylem mass; c, palisade parenchyma. 



Pig. 3. Cross section of root, x 78. a, large parenchyma cells, aqueous 

 tissue; b, small parenchyma cell of the pericycle; c, masses of phloem; 

 d, tracheal tubes. 



