CHAPTER VIII. 

 STRUCTURE OF STEMS. 



95. In the study of seeds and their germination (Chapters 

 II and III) it was found that certain seedlings, the corn, for ex- 

 ample, has one cotyledon, while the pea, bean, 



etc., have two cotyledons, or seed leaves. 

 Plants belonging to the first class are called 

 Monocotyledons, while those belonging to the 

 second class are called Dicotyledons. The 

 fact that most plants of the first class have 

 one cotyledon, and those of the second have 

 two cotyledons, led to the adoption of these 

 names. There are, however, other important 

 distinctions. The anatomy or structure of 

 the plants belonging to these two classes shows 

 certain points of agreement. Most of the 

 members of the monocotyledons possess one 

 type of structure, while the members of the 

 dicotyledons possess another type of structure. 



STRUCTURE OF THE STEMS OF 

 MONOCOTYLEDONS. 



96. The corn plant, the cereals like 

 wheat, the grasses, etc., are good examples of 

 monocotyledons , the stem is distinctly marked com plant, a mono- 

 off into nodes, or joints, and internodes. The 



leaf is attached at a node. The three parts in a typical leaf, 

 as in the corn, are as follows: The sheath surrounds the stem, 

 the blade is the free part of the leaf, the ligule is a slight mem- 



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