104 Flora of the Palouse Region 



racemes slender, 10-20 cm. long: flowers white, sweet-scented, 4-5 mm. long, 

 reflexed on short pedicels: calyx-teeth subulate, as long as the tube: pod 

 ovoid, 2-3 mm. long. Sparingly introduced. 



169. TRIFOUUM. 



Tufted or diffuse herbs: leaves mostly palmately, sometimes 

 pinnately, 3-foliolate; leaflets usually toothed; stipules united with 

 the petiole: flowers in heads or in umbel-like heads: calyx-teeth 5, 

 nearly equal: petals more or less persistent, the claws of all but 

 the standard united more or less below the stamen-tube: stamens 

 10, diadelphous or the tenth onl} r partly separate: pod small and 

 membranous, 1-6-seeded, included in the calyx. 



Heads subtended by an involucre. T. cyaThiferum. 

 Heads not subtended by an involucre. 



Heads longer than broad. T. arvexse. 

 Heads globose. 



Creeping: flowers white. T. repexs. 



Procumbent or ascending: flowers pinkish. T. hybridum. 



Erect: flowers red: peduncles short. T. praTENSE. 



Erect: flowers red: peduncles long. T. altissimum. 



T. cyathiferum Lindley. Annual, glabrous: stems weak, ascending, 10-30 

 cm. high: leaflets oblanceolate or obovate, serrulate, acute, obtuse or trun- 

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

 ceolate, 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, equall- 

 ing the corolla: pod 2-seeded. Springy gravelly places, rare. 



T. arvense E. Annual, erect, somewhat silky-pubescent throughout, 10- 

 30 cm. high: leaflets linear or oblanceolate, obtuse or notched, denticulate 

 near the apex, 1-2 cm. long; petioles mostly shorter than the leaflets; 

 stipules narrow, with long subulate tips: peduncles 2-4 cm. long: head ob- 

 long, dense, 1-2.5 cm - long: calyx silky-hairy, the subulate lobes longer than 

 the tube and the pink or whitish corolla. Sparingly introduced. 



T. repens E- Perennial, glabrous or sparsely pubescent, with creeping 

 stems, 10-30 cm. long, which root at the nodes: leaflets obovate, obtuse or 

 notched at apex, cuneate at base, denticulate, 1-2 cm. long; petioles elon- 

 gated; stipules narrow, acute: peduncles longer than the leaves: head globose: 

 flowers white, 6-10 mm. long, pedicelled, at length reflexed: calyx-teeth 

 acuminate, shorter than the tube. Everywhere introduced. 



T. hybridum L. Perennial, erect or decumbent, not creeping, glabrous 

 or nearly so, the stem 30-60 cm. long: leaflets obovate, obtuse or notched, 

 cuneate at base, sharply serrulate, 1-2.5 cm - l°ng; petioles about as long as 

 the leaflets; stipules membranous, ovate-lanceolate, acuminate: peduncles 

 elongated: heads globose: flowers pink or pinkish, 6-8 mm. long, on slender 

 pedicels, at length reflexed: calyx-teeth subulate, about as long as the tube, 

 much shorter than the corolla. Sparingly introduced. 



