cow GRASS. -^LUCERNE. 189 



profusely even where it was not observed in other 

 years, and hence such seasons pass under the term of 

 " clover years." It is not, apparently, so much relished 

 by stock as from its sweetness we should be led to 

 expect ; but it is, on the whole, to be cherished for per- 

 manent pastures, and improved, as it undoubtedly piay 

 be, by a proper selection and culture of varieties. For 

 an accurate analysis of this plant, the reader is referred 

 to a subsequent page. 



Cow Grass, Zigzag Clover, Perennial Clover 

 {Trifolium medium), grows on dry hills in Massachu- 

 setts, and has been introduced for cultivation in vari- 

 ous parts of the country, as a pasture plant. Its stems 

 are zigzag, smoothish ; leaflets oblong, entire, spotless ; 

 heads mostly stalked ; flower purple, and larger than in 

 red clover. 



Alstke, or Swedish Clover {Trifolium hybridum), 

 has also been introduced for cultivation on moist, strong 

 soils, but with what success I am not informed. It is 

 said to continue in the soil for many years, from its own 

 seeds, if left to mature. 



Suckling Eed Clover ( Trifolium filiforme) has also 

 been introduced and recommended for cultivation, but 

 has not come into general culture. 



Lucerne, Alfalfa (Medicago sativa), is shown in 

 Fig. 152. Leguminous plants of the genus Medicago 

 have been known and cultivated from time immemo- 

 lial. This particular species, lucerne, was brought from 

 Media to Greece, in the time of Darius, about five hun- 

 dred years before Christ, and its cultivation afterwards 

 extended among the Romans, and through them to the 

 south of France, where it has ever since continued to 

 be a favorite forage plant. It does not endure a climate 

 as severe as red clover, requiring greater heat and sun- 



