MEADOW PLANTS 41 



45. Alfalfa (Medicago sativa L.) is the most important 

 forage crop in the United States. In the irrigated regions 

 of the West it is almost the only forage plant grown and 

 is there used for both hay and pasture. Alfalfa was intro- 

 duced from Europe by the Spaniards and attained 

 importance in our western states simultaneously with 

 irrigation. Its use spread eastward in the arid and semi- 

 arid regions until it reached the borders of the timothy 

 region. Within recent years this crop has been success- 

 fully introduced in many parts of the East and South. It 

 does not thrive on an acid soil, hence the necessity of using 

 lime in many parts of the East in preparing the land for 

 alfalfa. Where a good stand is obtained, a permanent 

 meadow is formed, yielding cuttings every four to six 

 weeks during the growing season, two or three cuttings 

 in the more northern regions, as many as ten in the hot 

 southern valleys of California. The meadow lasts indefi- 

 nitely, but sooner or later suffers from the incursions of 

 various weeds and must be broken up and reseeded. As 

 alfalfa is not a grass, it will not be further discussed here, 

 but the student is referred for detailed information to 

 Farmers' Bulletin No. 339 from the United States Depart- 

 ment of Agriculture. 



46. The clovers are legumes belonging to the genus 

 Trifolium. Certain allied plants are also known as clover 

 but with a modifying term, such as bur clover {Medicago 

 arabica Huds.), sweet clover (Melilotus alba Desv.), Japan 

 clover {Lespedeza striata (Thunb.) Hook. & Arn.), all 

 belonging to the family Leguminosae. The true clovers 

 include the common red clover {Trifolium pratense L.), 

 which is usually referred to merely as clover, alsike {T. 

 hybridum L.), white clover {T. repens L.), and crimson 

 clover {T. incarnatum L.). The first two are used for 



