LESSON I 

 THE GRASS FAMILY 



To most persons grass is almost any green vegeta- 

 tion of rather low growth, especially such as may be 

 grazed. To the student of plants, a grass is a 

 member of the natural family Poaceae, or Gramineae, 

 distinguished by its structure. 



Grasses are herbs with round or flattened (never 

 3-angled), usually hollow stems (culms) solid at 

 the joints (nodes), and 2-ranked, alternate, parallel- 

 veined leaves, composed of two parts, the sheath, 

 which surrounds the culm like a tube split down one 

 side, and the blade, which is usually strap-shaped, 

 flat, folded, or with rolled margins. At the junction 

 of the sheath and blade, on the inside, is a small 

 appendage (the ligule); this is commonly thin in 

 texture; sometimes it is only a ring of hairs, rarely 

 it is obsolete. The plants may be annual or peren- 

 nial. The root, stem, and leaves are the vegetative 

 part of the plant (Fig. 1). These are all that are 

 concerned with the life of the individual plant. The 

 flowers have to do with perpetuating the species. 

 In grasses the vegetative parts are more uniform 

 and characteristic than in most other families. 



Having stem and leaves of any plant, it can always 

 be readily decided whether or not it is a grass. The 



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