Spring Flora of Oklahoma 
75 
V. TRIFOLIUM (Tourn.) L. 
Annual, biennial, or perennial herbs. Leaves petioled, of 
3 toothed or serrate leaflets. Stipules united to the petioles. 
Flowers white, yellow, or red, in heads. Calyx 5-cleft, the 
teeth nearly equal, awl-shaped. Keel shorter than the 
wings. Stamens diadelphous. Pod smooth, 1-6-seeded, 
scarcely opening. 
Flowers sessile, or very nearly so; heads dense, ovoid, 
oval or globose. 1. T. yratense. 
Flowers pedicelled; heads umbel-like, globose. 
Ascending or procumbent; flowers pink, pinkish, or 
purple. 2. T. hybridum. 
Creeping; flowers white or pinkish. 3. T. reyens. 
1. Trifolium pratense L. Red Clover. Perennial, more or less 
pubescent, branching. Leaves long-petioled. Stipules ovate, strongly 
veined, subulate-tipped. Leaflets short-stalked, oval, oblong, or obo- 
vate, finely toothed, often with a dark, triangular spot near the 
center. Flowers red. Calyx teeth bristle-shaped hairy. Pod 1-3- 
seeded. 
Moist waste places. April-November. 
2. Trifolium hybridum L. Alsike Clover. Perennial, erect or 
ascending. Leaflets ovate, the margins fringed with hairs, serrulate 
with sharp, pointed teeth, rounded at the apex. Stipules prolonged 
into bristle-points. Flowers rose color and white. 
In waste places. May-October. 
3. Trifolium repens L. White Clover. Resembling preceding 
species but the branches creeping, often rooting at the nodes. Leaf¬ 
lets obovate or obcordate, denticulate. Head globose. Flowers white, 
finally reflexed. Stipules ovate-lanceolate. 
Waste places and lawns. May-December. Common. 
IV. PSORALEA (B. Juss.) L. 
Perennial herbs. Whole plant glandular dotted. Leaves 
mostly 3-5 foliolate. Flowers in axillary or terminal spikes 
or racemes. Calyx 5-cleft, the lobes nearly equal. Stan¬ 
dard ovate or orbicular, keel incurved, obtuse. Stamens 
monodelphous or diadelphous, 5 of the anthers often unde¬ 
veloped. Ovary nearly sessile. Pod included in the calyx, 
often wrinkled, indehiscent, 1-seeded. 
