82 



BOTANICAL GAZETTE 



[JANUARY 



Silicon was found m the pericarp, as was shown by heating a 

 dry section of the tissues with phenol. Tannins were found in the 

 glumes and in the outer coats of the seeds, where red and purplish 

 colors were observed, which were probably due to the oxidized 

 tannins . 



Two sizes of starch grains were found. The endosperm cells 

 were filled with large sized starch grains, while the pericarp integu- 

 ment, the pedicel, and the basal seta had smaller grains in them. 



Neither dextrin nor glucose was present in the embryo or in the 

 endosperm, but considerable was present in the hulls. Amylo- 

 dextrin was found in all of the endosperm cells in rather large 

 quantities. The layers of the cells of the caryopsis outside of 

 the fat-containing endosperm cells all gave a positive reaction for 

 glucose when treated with copper tartrate and sodium hydroxide. 



TABLE VI 



MlCROCHEMISTRY OF SUDAN 



SEED 



Part of seed 



V 



o 





Pedicel 



Glume 



Basal seta 



Lodicule 



Pericarp 



Aleurone layer. . 



Endosperm 



Epithelial layer . 



Scutellum 



Embryo node. . . 



Radicle 



Coleorhiza 



Plumule 



+* 



+ 



+ 

 + 



Coleoptile 



-f 



+ 

 + 

 + 

 + 

 + 

 + 



r. 



O 



c 



u 



C 



+ 



+ 



+ 



« . - v 



++ 

 ++ 



'3 



+ 

 + 



in 



+ 





+ + 



+ 

 + 

 + 

 + + 

 + + 

 + 

 + 



§ 



^ 



+ 



+ 

 + 

 + 

 + 

 + 

 + 





x. 



in 



+ 



+ 



+ 



+ 



+ 



8 



3 



o 



++ 



+ 



is 

 < 



* += present; + + = present in large amount. 



In conclusion, I wish to acknowledge my obligations to Pro- 

 fessor William Crocker, under whom this work was done, for his 

 advice and valuable criticisms; to Dr. S. H. Eckerson for her 

 untiring interest and advice relative to the microchemistry; and to 

 Professor F. C. Koch for his helpful suggestions in the methods of 

 chemical determinations involved. 



Bureau of Plant Industry 

 Washington, D.C. 



