LEGUMINOSAE (PULSE FAMILY) 



233 



"soil renovators," partly by reason of their large and deeply 

 penetrating roots, which break up the soil, mellow, aerate, and 

 drain it, and then, by their death and rapid decay, furnish it with 

 humus ; also they bear on their roots many tubercles in which live 

 those beneficent, nitrogen-gathering bacteria that make the earth 

 better for their having lived in it. For this reason, Sweet-clover is 

 often used to prepare the ground for the growing of Alfalfa. The 

 hay is nutritious, but cattle do not like its 

 strong odor and will not eat it until they have 

 been "educated to the taste," which is usually 

 done by turning them into the Sweet-clover 

 field early in spring, when no other green 

 forage is available. (Fig. 165.) 



Stems three to ten feet tall, round, slender, 

 somewhat woody, many-branched, smooth 

 except the young growing twigs, which are 

 finely hairy. Leaves pinnately three-foliolate, 

 the leaflets oblong to elliptic, obtuse or some- 

 times even notched at the tip, very finely 

 toothed, the foot-stalk of the middle one 

 bent slightly upward ; petioles usually shorter 

 than the blades. Flowers in long, slender, 

 one-sided, axillary racemes, white and very 

 fragrant; corolla about a quarter-inch long, 

 with narrow petals, the standard longer than 

 the wings or the keel. Pods ovoid, wrinkled, 

 net-veined, one- or two-seeded. When in the 

 soil the seeds are said to retain their vitality FIG. 165. White 

 for fifty years or more ; they are sometimes Sweet-clover (Melilo- 



, iic i 11 tus alba) . X J. 



used by unscrupulous dealers for the adulter- 

 ation of Alfalfa seed, which is somewhat similar in appearance 

 but much more expensive. 



Means of control 



Close cutting as soon as the first flowers open ; the plants will 

 immediately sprout thick stools of flowering stalks, requiring a 

 second and perhaps a third cutting, but if no seed is allowed to 

 mature and drop into the soil there will be no further trouble, for 



