Trifolium Leguminosae 595 



2. Melilotus officinalis (L.) Lam. Yellow Sweetclover. Map 

 1215. This species has been sparingly sown for pasture and fodder and 

 has escaped like the preceding species but it is much more aggressive. 



Nat. of Eurasia; widely naturalized in N. A. 



3690. TRIFOLIUM [Tourn.] L. Clover 



• 



Flowers sessile or nearly so, crowded; corolla pink, purple or rose. 

 Leaflets narrow, mostly 2-6 mm wide, linear to oblanceolate; heads mostly longer 



than wide; plants annual, erect 1. T. arvense. 



Leaflets mostly more than 6 mm wide, oval, ovate, obovate or cuneate-obovate ; heads 

 globose or subglobose. 



Plants pubescent, ascending, perennial; flowers purplish 2. T. pratense. 



Plants glabrous, ascending or diffuse, annual; flowers rose 3. T. resupinatum. 



Flowers on short pedicels; heads looser. 

 Flowers, white, purplish or crimson. 

 Heads much longer than wide; leaflets pubescent; flowers crimson. (See excluded 



species no. 388, p. 1065.) T. incarnatnm. 



Heads globose; leaflets glabrous or nearly so; flowers white or purplish. 

 Calyx lobes 2-3 mm long, about as long as the tube. 



Plants stoloniferous, creeping; heads on long peduncles, arising from prostrate 



stems 4. T. repens. 



Plants not stoloniferous, ascending; heads on peduncles not arising from pros- 

 trate stems 5. T. hybridum. 



Calyx lobes mostly about 4 mm long, much longer than the tube. 



Plants stoloniferous; sinuses of the calyx pubescent. (See excluded species 



no. 390, p. 1066.) T. stoloniferum. 



Plants not stoloniferous ; sinuses of the calyx not pubescent. 



Calyx pubescent. (See excluded species no. 389, p. 1065.) . . . . T. reflexum. 



Calyx glabrous 6. T. reflexum var. glabrum. 



Flowers yellow. 



Terminal leaflet longer stalked than the lateral ones; stipules ovate. 



Heads 20-40-flowered; corolla conspicuously striate 7. T. procumbens. 



Heads 5-12-flowered; corolla scarcely striate 8. T. dnbium. 



Terminal leaflet not longer stalked than the lateral ones; corolla conspicuously 

 striate; stipules linear-lanceolate 9. T. agrarium. 



1. Trifolium arvense L. Rabbit-foot Clover. Map 1216. In dry 

 sandy soil along roadsides and in pastures, open woodland, and fallow 

 fields. 



Nat. of Eurasia; Que. and Ont. to Mo., southw. to Fla. and Tenn. 



2. Trifolium pratense L. Red Clover. Map 1217. This species is 

 much sown for pasture and fodder and has frequently escaped in all parts 

 of the state to roadsides, waste places, and fallow fields. 



Nat. of Eurasia; widely naturalized in N. A. 



3. Trifolium resupinatum L. Strawberry Clover. This species was 

 discovered north of Indianapolis by W. N. Clute, May 9, 1932. He says 

 it occurs for a mile along the old canal and along roadsides. 1 



Greece to Persia; Mass., Pa., and Wis. southw. to Ala. 



'Clute (Amer. Botanist 45:32. 1939) says: The severe winter of 1935-36 ap- 

 parently killed all the plants. 



