FLORA OF THE DISTRICT OF COLUMBIA. 183 



2. GROT AL ARIA L. 



1. Crotalaria sagittalis L. Rattlebox. 



Dry open soil; frequent. July-Aug. Eastern U. S. to Mex. 



3. LUPINUS L. 



1. Lupinus perennis L. Wild lupine. 



Dry or wet, sandy soil; frequent. Apr.-May. Eastern U. S. 



4. GENISTA L. 



1. Genista tinctoria L. Dyeweed. 



Waste ground at Fourteenth and Decatur Streets {Steele). Native of Eur. and Asia; 

 sparingly naturalized in N. Amer. 



5. CYTISUS L.» 



1. Cytisus scoparius (L.) Link. Broom. 



Established in Rock Creek Park and a few other localities in the same region. 

 Apr.-June. Native of Eur.; naturalized in many parts of N. Amer. 



6. MEDICAGO L. 



Flowers violet or blue; leaflets more than twice as long as broad 1. M. sativa. 



Flowers yellow; leaflets less than twice as long as broad, often as broad as long. 



2, M. lupulina. 

 Medicago arahica (L.) Huds. ( .¥. marulata Sibth.) has been reported from waste 

 ground in Washington. 



1. Medicago sativa L. Alfalfa. 

 Occasional in waste ground. June-July. Native of Asia; widely cultivated for 



fodder, and often escaping. 



2. Medicago lupulina L. Black medic. 

 Fields and waste ground; frequent. May- July. Native of Eur. and Asia; widely 



naturalized in N. Amer. 



7. MELILOTUS Mill. 



Flowers white; standard petal slightly longer than the wing petals 1. M. alba. 



Flowers bright yellow; standard about as long as the wings 2. M. officinalis. 



1. Melilotus alba Desv. White sweet clover. 

 Waste ground; abundant. May-Aug. Native of Eur. and Asia; widely natural- 

 ized in N. Amer. 



2. Melilotus officinalis (L.) Lam. Yellow sweet clover. 

 Waste ground; frequent. May-Aug. Native of Eur. and Asia; widely naturalized 



in N. Amer. 



8. TRIFOLIUM L. Clover. 

 Flowers yellow. 

 Terminal leaflet sessile, like the lateral ones; heads of flowers 12-20 mm. long; 



stipules linear or nearly so 1. T. agrarium. 



Terminal leaflet slender-stalkea; heads of flowers all or nearly all less than 12 mm 

 long; stipules ovate. 

 Flowers 20-40 in each head^ standard petal conspicuously furrowed. 



2. T. procumbens. 



Flowers about 10 in each head; standard only slightly furrowed... 3. T. dublum. 



Flowers white, red, or purple. 



Heads of flowers much longer than broad, long-stalked. Calyx teeth long-hairy; 



plants very hairy. 



Corolla crimson, equaling or longer than the calyx lobes; leaflets as long as broad 



or nearly so 4. T. incarnatum 



