160 Guayule. 



Description of Plate 38. 



1. Transverse section, definitive stem, to show primary plan of canals. 



2. Petiole, to show the canals of a large foliage leaf. Dorsal canals of cauline 



origin. Ventral canals, foliar. 

 3-5. First foliage leaf. 

 6-9. Another (first) foliage leaf. 

 10-18. Definitive leaf. 





