SEEDLINGS 



III 



A good way to study the small, delicate parts of plants 

 is to place them between two thin, clear pieces of glass and 

 hold up to the light. Even without a lens many peculiari- 

 ties of structure can in this way be made apparent to the 

 eye. 



Instead of corn, seedlings of wheat or oats may be used, 

 and if time permits it would be well to examine and com- 

 pare the two. 



151. Organs of Vegetation. — These three organs, root, 

 stem, and leaf, are all that are necessary to the individual 

 life of the plant. They are called organs of vegetation 

 in contradistinction to the flower and fruit, which consti- 

 tute the organs of reproduction. The former serve to 

 maintain the plant's individual existence, 

 the latter to produce seed for the propa- 

 gation of the species, so we find that the 

 seed is both the beginning and the end of 

 vegetable life. 



152. Polycotyledons. — The pine is very 

 difficult to germinate, requiring usually 

 from 1 8 to 2i days, but if a seedling can 

 be obtained it will make an interesting 

 study. By soaking the mast for 24 hours 

 and planting in damp sand kept at an even 

 temperature of not less than 23° C. (74° or 

 75° F.) a few specimens may be obtained. 



246. — Seedling of 

 pine (Gray). 



153. Seedlings of Dicotyledons. — Sketch, without remov- 

 ing it, a bean seedling that has just begun to show itself 

 above ground ; what part is it that protrudes first .■" Sketch 

 in succession four or five others in different stages of 

 advancement. Notice how the hypocotyl is arched where 

 it breaks through the soil. Can you account for this ? 

 Does it occur in the monocotyledons examined .' Almost 

 all dicotyledons exhibit this peculiarity in germination ; 

 can you see what causes it ? Do the cotyledons appear 

 above ground ? How do they get out ? Can you perceive 



