FLORA OF THE DISTRICT OF COLUMBIA. 183 



2. CROTALARIA L. 

 1. Crotalaria sagittalis L. Rattlebox. 



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



3. LTJPINTJS 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 leas than twice as long as broad, often as broad as long. 



2. M. lupulina. 

 Medicago arabica (L.) Huds. (M. maeulata Ribth.) 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. TRIFOLnJM 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 nun 

 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. dubium. 



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 * T. incarnatum 



