606 FABACEAE 



subulate-lanceolate, the longer ones exceeding the tube in length : corolla yellow, 3-4 mm. 

 long ; standard with a suborbicular blade, surpassing the wing-petals. 



In fields and waste places, throughout the United States and southern British America. Natural- 

 ized from Europe. Spring to fall. 



3. Trifolium agrarium L. Foliage bright green. Stems more or less diffusely branched, 

 often from the base, the branches 2-8 dm. long, ascending or reclining, strigillose : leaves 

 numerous , petioles shorter than the leaflets on the upper part of the branches ; stipules 

 somewhat acuminate : leaflets 3, the blades broadest above the middle, the terminal one no 

 longer-stalked than the lateral, all denticulate : peduncles becoming 1-5 cm. long, finely 

 pubescent: racemes oblong or oval, 12-20 mm. long, densely many-flowered : calyx 3. 5-4 

 mm. long, short-pedicelled ; lobes linear-subulate, longer than the ribbed tube : corolla 

 deep yellow, 4-5 mm. long, becoming reflexed, turning brown in age. 



In fields and waste places, Nova Scotia to Ontario, Iowa and Georgia. Naturalized from Europe. 

 Spring and summer. 



4. Trifolium arvense L. Annual, villous-lanuginose. Stems erect, 1-4 dm. tall, 

 usually branched throughout : leaflets 3, the blades linear to oblanceolate, 1-2.5 cm. long, 

 notched or truncate at the apex, often mucronate, entire or slightly two-toothed : peduncles 

 surpassing the subtending leaves : heads dense, oblong or cylindric, 1-3 cm. long: calyx 

 gray ; tube finally ovoid ; lobes subulate, longer than the tube : corolla whitish, surpassed 

 by the calyx lobes : standard somewhat longer than the "wing-petals. 



Along roadsides, in dry fields and on banks, throughout eastern North America. Naturalized from 

 Europe and Asia. Summer. 



5. Trifolium prate"nse L. Perennial, more or less densely pubescent. Stems com- 

 monly branched at the base, the branches erect or ascending, 2-7 dm. long : leaflets 3, the 

 blades oblong, elliptic or oval, varying to ovate or obovate, 1-4 cm. long, rounded or 

 notched at the apex, sometimes apiculate, denticulate, often blotched : peduncles commonly 

 shorter than the subtending leaves : heads subglobose to ovoid, 2.5-3 cm. thick : calyx 

 villous ; tube long-campanulate ; lobes filiform, the longer ones often surpassing the 

 tube : corolla red, purple or white, nearly 1.5 cm. long ; standard elongated, surpassing 

 the wing-petals. 



In fields, meadows and cultiv ated grounds, throughout the United States and southern British 

 America. Widely cultivated and naturalized from Europe. Spring to fall. 



6. Trifolium leflexum L. Annual or biennial, more or less densely villous or downy, 

 destitute of runners. Stems simple and erect or usually branched at the base, the branches 

 ascending or spreading, 1-5 dm. long : leaflets 3, the blades oblong, elliptic-obovate to 

 suborbicular, 1.5-3 cm. long, rounded or emarginate at the apex, often mucronate, dentic- 

 ulate : peduncles longer or shorter than the subtending leaves : calyx often glabrous ; 

 tube campanulate, very short ; lobes lanceolate-subulate, much longer than the tube : 

 corolla 6-10 mm. long ; standard red or purple, surpassing the white keel and wing- 

 petals. 



In waste places, fields, dry woods and meadows, Ontario to Nebraska, Florida and Texas. Spring. 



7. Trifolium stolon iferum Muhl. Perennial, glabrous, producing runners at the 

 base. Stems simple and erect or branched at the base, the branches widely spreading, 1-3 

 dm. long : leaflets 3, the blades obovate, broadly cuneate or nearly orbicular, 1-3 cm. in 

 diameter, rounded or notched at the apex, denticulate : peduncles surpassing the subtend- 

 ing leaves : calyx ribbed ; tube campanulate ; lobes subulate, twice or thrice as long as the 

 tube : corolla white tinged with purple, 8-12 mm. long ; standard involutely folded, sur- 

 passing the wing-petals. 



In open woods and on prairies, Ohio to Nebraska, Tennessee and Missouri. Spring and summer. 



8. Trifolium Bejaiiense Moric. Annual, sparingly pubescent. Stems erect, or 

 branched at the base, the 'ranches ascending or decumbent, 1-2 dm. long, simple or 

 branching above : leaflets 3, the blades obovate or cuneate, 5-10 mm. long, rounded or 

 emarginate at the apex, denticulate : peduncles several times longer than the subtending 

 leaves : heads many-flowered, 1.5-2 cm. thick : calyx reticulated, 2-lipped ; tube campanu- 

 late ; lobes unequal, the upper one nearly distinct, the rest shorter than the tube : corolla 

 pale, becoming brown, somewhat longer than the calyx ; standard and wing-petals toothed, 

 the former surpassing the latter. 



On prairies, Texas. Spring. 



9. Trifolium Caroliniamim Michx. Perennial, slender, pubescent. Stems usually 

 branched at the base, the branches ascending or decumbent, 1-3 dm. long, often sparingly 

 branched above : leaves with slender petioles : leaflets 3, the blades obovate or cuneate, 

 5-12 mm. long, rounded or emarginate at the apex, denticulate, acute at the base : pe- 

 duncles usually many times longer than the subtending leaves : calyx pilose, reticulated ; 



