CHAPTER IV, 



GERMINATION, GROWTH, TISSUE TENSION. 

 I. TYPICAL SEEDS AND SEEDLINGS. 



168. Types of Seeds and Seedlings. The chief 

 types selected for study may be classified as follows : 



Dicotyledons. 



Non-endospermic. Hypogeal: Broad Bean ( 171- 



173). 



Epigeal -.Sunflower ( 175). 

 Endospermic : Castor Oil ( 177). 



Monocotyledons . 



Endospermic. Hypogeal : Maize ( 178-180). 

 Epigeal : Onion ( 182). 



Other seeds and seedlings should also be studied for 

 comparison with these and for special points in the struc- 

 ture and biology of seeds and seedlings. Soak the various 

 seeds in water, and make successive sowings both indoors 

 and in a garden border so as to have plenty of material 

 for observation and experiment. 



169. Germination Jars. (a) Take a large wide- 

 mouthed glass jar wiped dry inside, and a piece of thick 

 blotting-paper cut rectangular with one side equal in length 

 to the height of the jar and the other a few inches longer 

 than the circumference of the jar. Roll the paper and 

 insert it in the jar, then fill up the jar with sawdust, 

 keeping the paper pressed against the inner side of the 

 glass. Place seeds in different positions between paper 



132 



