Seeds and Seedlings. 9 



14. Carefully remove the shell or testa from a seed and 

 note any structural details thus brought to light. Split the 

 shelled seed longitudinally through its greater diameter, 

 and make drawings of the internal structures. Split 

 another shelled seed longitudinally through its lesser 

 diameter, taking care to cut the structures already dis- 

 covered exactly through the middle. Make a 'drawing 

 from this point of view, sharply demarking the limits of 

 the different structures. Make a cross section of a shelled 

 seed a little below the middle, and draw the cut surface, 

 bringing out clearly the outlines of the different parts. 

 These drawings should all be made to the scale, x 3. 



Germinating Castor Bean. 



15. Draw the castor bean in the first stages of germina- 

 tion, showing how the seedling protrudes through the shell. 

 Scale, x 2. 



1 6. Remove the testa from a seed in the first stages of 

 germination, and split it in halves longitudinally through 

 the broad diameter. Draw from the point of view of the 

 interior surface. Scale, x 3. Split another seed in the 

 same stage of germination longitudinally through the nar- 

 row diameter, taking care to halve all of the structures, 

 and draw from the cut surface to the same scale. 



17. Treat, in a similar manner, seedlings in later stages 

 of germination, and call attention to any new structures 

 which were not seen in the ungerminated seed. Follow 

 the changes which the different parts undergo up to the 

 stage where all reserve food materials have been used up. 



1 8. In your notes, answer briefly the following ques- 

 tions : Where and how does the seedling crack the hard 

 shell ? How does the seedling get above the soil ? How 

 does the young plant get the food materials which are 



