. NORTH-CAEOLINA GEOLOGICAL SUEYEY. 139 



kind, and a succession follows till late in autumn. Some are 

 found fitted for food just as the snows are about to cover the 

 ground. The farmer will not fail to profit by this succession. 

 The early and late pasturage shortens a winter two weeks or 

 more. The end is attained by mixing the seed of the plants 

 we wish to cultivate. The advantage is not confined wholly 

 to a successive supply of food, but a greater quantity grows 

 upon a given area than if it was cultivated with one. 



103. The grasses proper consist of many genera, contain- 

 ing each many kinds or species. They constitute a very nat- 

 ural family of plants resembling each other in their external 

 characteristics, and also in their internal organization and 

 chemical constitution. 



I have had occasion to speak of the chemical constitution 

 of plants, and have called some, as the clovers, lime plants, 

 and others, potash plants. The grasses differ from these ; in- 

 stead of lime or potash, they contain silica, though potash is 

 sometimes present in large proportions, and must necessarily 

 be present to a certain extent in combination with silica, for no 

 doubt it is required to give it solubility. 



The design and construction of the grass plant, as it was to 

 be deficient in woody fibre, required some hard substance to 

 sustain its slender and delicate frame. This frame work is, 

 in a portion of the family, a hollow cylinder, or several hol- 

 low cyinders connected by impervious solid joints, sometimes 

 called nodes. Others are provided with a pith as the corn 

 stalk. Their leaves are always formed upon one plan, being 

 long and tapering, or lanceolate with ribs running parallel 

 with each other their entire length and never anastomosing. 

 The middle one is stronger than the rest, and more prominent. 

 The leaf terminates in a sheath below, which grasps or en- 

 closes the stem. The root is usually fibrous, sometimes bul- 

 bous, and creeping ; it frequently becomes troublesome to 

 extirpate as it emits roots from the numerous joints with 

 which it is provided. The flowers or blossoms are small and 

 never showy. They are simple, having envelopes which are 

 in keeping with the family characteristics. Thus, there are 

 provided two grassy outside leaves, answering to the calyx 



