4 REPRESENTATIVE PLANTS 



axis, the little plant, having the same parts as in the bean ; 

 that part nearest to the pointed end of the seed being the 

 hypocotyl. The stained part is the endosperm. What sub- 

 stance does it contain? About how much of the seed does 

 it occupy? What, in purpose or use to the plant, does it 

 correspond to in the bean? Observe in all these operations 

 that the corn seed cannot be split into halves, as can the 

 bean and all other dicotyledonous seeds. All such undivid- 

 able seeds are monocotyledoyious. Name other kinds, if pos- 

 sible, having this feature. 



Drawings. Make enlarged drawings showing the face 

 views, a marginal view, and all of the above sections, care- 

 fully labeled. 



3. Pine Seeds 



Where procured. The seeds of any available species of 

 pine may be used. Pinon " nuts *' may be found iu fruit 

 stores in large cities. Other conifer seeds may be substi- 

 tuted, but pine seeds are larger and therefore better. 



External features. Soak a number of seeds for several 

 hours. Examine one for any external features. What part 

 is occupied by the seed proper and what part by the broad 

 and thin wing 9 What use has the wing? Throw a seed 

 up into the air and watch closely as it falls. What 

 would happen if a strong wind were blowing on the falling 

 seed? 



Sections. With a sharp knife, make some long sections 

 of the soaked seeds. Observe the seed coat on the outside 

 and a thin papery layer next within (the nucellus remnant). 

 The mass of the seed is the endosperm. What color is it ? 

 Embedded in this is the young plant or embryo. Examine 

 this very carefully (m) and find the long stem, hypocotyl, 

 and a cluster of tiny structures near the blunt end (upper) 

 of the seed, the many cotyledons. The plumule is hidden 

 from view. 



