74 



GROWTH OF SEEDLINGS 



60. GROWTH 



Object. To learn how a corn plant comes up through 

 the soil. 



Apparatus. Corn, flowerpot, and soil. 

 Method. Plant the corn as in the preceding Experi- 

 ments. After a few days observe how this plant forces 



its way through the soil 

 and into the air. 



Conclusion. State the 

 result of your observa- 

 tions. 



Note. The preceding 

 four Experiments have been 

 introduced to illustrate 

 three ways or types char- 

 acteristic of dicotyledon- 

 ous plants, and one way in 

 which monocotyl plants 

 come forth from the soil. 

 Thus the squash develops 

 an arch and peg by which it 

 forces the shell open. The 

 peg holds down the shell, 

 and the arch breaks through 

 the soil. The bean has no 

 peg, but the arch breaks 

 ground, dragging the cotyledons up backward. In the pea we find' 

 the cotyledons remaining underground since they can never function 

 as foliage, and the ground is broken by a very small arched plumule. 

 In corn and most other monocotyls there is no arch, but the plumule 

 consists of a leaf rolled up so closely as to be able to puncture the 

 soil. The onion seed, however, forms a fine arch in germinating. 



Suggestion. From visits to the woods, parks, or gardens 

 in early spring find out to which type of dicotyledons each 



FIG. 22. Germinating corn. 



