Seeds and Their Germination. 



17 



Fig. 12. A. A ketnel of corn. s. 

 The stem which usually remains on 

 the cob. e. Position of the embryo 

 (chit). B. Embryo magnified. C. 

 Section of the embryo, showing plu- 

 mule (/) and caulicle (c). 



Compare your drawings with those shown on this page. 



Evidently the embryos of corn 

 and wheat are very different from 

 those of the seeds which we have 

 before examined. Instead of two 

 cotyledons there is one enclosing 

 and growing fast to the center of a 

 stem-like organ which is not at once 

 recognized as caulicle and plumule. 



Note the work in the jar. Put 

 the remainder of the corn and wheat in sprouting dishes. 



EXERCISE 10. 



This diagram shows the parts of a dicotyledonous*' em- 

 bryo which has been growing a 

 week or more. On the right the 

 names and dotted lines indicate 

 the parts manifestly distinct in 

 the embryo before it begins to 

 grow. On the left the growing 

 plumule stem or epicotyl, the 

 hypocotyl, and the root are 

 shown. The hypocotyl is that 

 part of the caulicle above the 

 side roots. It is the base of the 

 stem, or that portion of it below 

 the cotyledons. 



Observe the condition of all 



a/e. 



Canticle: 



Fig. 13. Diagram showing the parts of 

 a germinating embryo of an exogen. 



* . e. , one with two cotyledons. Corn and wheat are monocotyledonons. 



