LEGUMINOSAE. 219 



Heads on axillary peduncles; flowers pedicelled. 



Flowers white; stems creeping. T. repens. 



Flowers pink; stems procumbent. T. hybridum. 



Heads on terminal peduncles; flowers sessile. 



Calyx-teeth plumose. T. eriocephalum. 



Calyx-teeth not plumose. 



Flowers red ; stipules aristate. T. pratense. 



Flowers whitish; stipules not aristate. T. longipes. 



Annual; roots fibrous. 

 Calyx-teeth plumose. 



Heads ovate; flowers dark purple. T. albopurpureum. 



Heads oblong; flowers pink. T. arvense. 



Calyx-teeth not plumose. 



Corollas yellow, becoming papery in age. 



Heads 20-40-flowered ; standard distinctly 



striate. T. procumbens. 



Heads 3-15-flowered; standard faintly 



striate. T. dubium. 



Corollas pink, not becoming papery. 



Teeth of the calyx scarious-margined and 



ciliate. T. ciliolatum. 



Teeth of the calyx not scarious-margined 



nor ciliate. 

 Leaflets shallowly notched at apex; 



calyx glabrous. T. gracilentum. 



Leaflets deeply notched at apex; calyx 



hairy. T. hallii. 



Trifolium flavulum Greene. Annual, glabrous and somewhat fleshy; 

 stems 20-40 cm. high; leaflets obovate, obtuse, denticulate; stipules ovate, 

 entire; heads globose, large, the involucre cleft into entire acuminate lobes; 

 flowers large, reddish or yellowish, 2-2.5 cm. long; calyx-teeth triangular, 

 acute. 



Sparingly introduced from California. Perhaps not specifically distinct 

 from T. fucatum Lindl. 



Trifolium cyathiferum Lindl. Annual, glabrous; stems weak, ascending, 

 10-30 cm. high; leaflets oblanceolate or obovate, serrulate, acute, obtuse or 

 truncate, cuneate at base, 1-2 cm. long; petioles slender; stipules ovate or 

 lanceolate, laciniate; peduncles longer than the leaves; heads commonly 1.5 

 cm. broad; involucre large and conspicuous, whitish with green margin, 

 many-nerved, with short sharply-toothed lobes; flowers whitish; calyx mem- 

 branous, prominently 5-nerved, the nerves prolonged and branched, equalling 

 the corolla; pod 2-seeded. 



Very rare in our limits but common east of the Cascade Mountains; Lake 

 Crescent, Webster; Vancouver Island, British Columbia, Macoun. 



Trifolium microcephalum Pursh. Annual, erect or spreading, soft villous; 

 stems 5-30 cm. long; leaflets obovate, usually retuse, serrulate, 8-12 mm. 

 long; petioles slender; stipules entire, acuminate; heads small, many-flowered; 

 involucre membranaceous, about 9-lobed, the lobes 3-nerved, entire; calyx 

 hairy, the teeth subulate; corollas pale pink; pods glabrous, 1 -seeded. 



In sandy soil, common. 



Trifolium microdon Hook. & Arn. Very much like T. microcephalum 

 but the cup-shaped involucre nearly enclosing the head; calyx glabrous. 

 Sandy soil, near the seacoast. 



Trifolium fimbriatum Lindl. (T. spinulosum Dougl.) Perennial by 

 creeping rootstocks, glabrous throughout; branches prostrate or ascending, 



