152 Guayule. 



DESCRIPTION OP PLATE 34. 



1. Transverse section of a peduncle. The mechanical tissues are hatched. 



2. Lower epidermis of the cotyledon of a field seedling. To accompany figs. 



4 and 7. 



3. Same, seedling grown in shade (to accompany figs. 6 and 9). 



4, 7. Cotyledon of a field seedling. 



5, 8. Cotyledon of a seedling grown in soil with a high saline content. 



6, 9. Same, grown with abundant water and shade. 



