118 ELEMENTS OF BOTANY. 



ard oblong, much longer than the wings or keel : stamens 10, 

 diadelphous ; ovary sessile ; legume 1-several-seeded, coiled, 

 indehiscent, often spiny. 



1. M. SATivA L. Alfalfa. Perennial ; stems erect, branching, 

 pubescent when yomig, becoming smooth with age, 2-3 ft. high ; 

 leaves short-petioled ; leaflets obovate, sharply dentate towards the 

 apex, obtuse or sometimes emarginate or mucronate ; stijjules lanceo- 

 late, entire ; flowers blue, small, in rather close spikes ; legumes 

 pubescent, coiled, few-seeded. April-September. Introduced from 

 Europe, and cultivated for hay and pasture. 



2. M. Arabica All. Bur Clover. Annual ; stem procumbent, 

 glabrous or slightly pubescent, 1-3 ft. long ; leaves long-petioled ; 

 leaflets obcordate, toothed above, usually with a dark spot near the 

 center ; stipules inequilateral, incised or toothed ; flowers small, yel- 

 low, in globose spikes; mature legume nearly globose, several times 

 coiled, reticulated and spiny-toothed. April-June. Introduced from 

 Europe and often cultivated for pastures. 



V. MELILOTUS. 



Annual or biennial herbs ; leaves petioled, trifoliate ; 

 flowers small, white or yellow, in dense axillary and terminal 

 racemes ; calyx 5-toothed, the teeth nearly equal ; standard 

 erect, wings and keel cohering ; stamens 10, diadelphous ; 

 legume longer than the calyx, 1-4-seeded. 



M. ALBA Desv. Melilotus. Biennial; stem erect, branching, 

 smooth or the young branches slightly pubescent ; leaflets oblong or 

 oblanceolate, rounded or truncate at the apex, serrate; stipules 

 small'; racemes long, slender, erect; flowers white; standard longer 

 than the wings and keel ; legume ovoid, rugose, drooping, mostly 

 1-seeded, scarcely dehiscent. April-October. Common on lime soil 

 and widely cultivated. 



VI. TRIFOLIUM. 



Annual, biennial or perennial herbs ; stems more or less 

 diffuse ; leaves petioled, trifoliate ; leaflets toothed or ser- 

 rate ; stipules adnate to the petioles ; flowers white, yellow 

 or red, in heads ; calyx 5-cleft, the teeth nearly equal and 

 subulate ; petals Avithering-persistent, keel shorter than the 

 wings ; stamens diadelphous ; legume smooth, 1-6-seeded, 

 scarcely dehiscent. 



