FABACEAE 605 



2. Melilotus officin&lis (L. ) Lam. Foliage glabrous, or twigs sparingly pubescent. 

 Stems erect or spreading, 3-10 dm. long, more or less branched : leaflets 3, the blades 

 narrowly oblong, oblanceolate or oval, 1-3 cm. long, rounded or truncate at the apex, 

 sharply serrate, bright green above : racemes 1-12 cm. long : flowers sometimes secund : 

 calyx campanulate ; lobes shorter than the tube : corolla yellow, 5-6 mm. long ; standard 

 and wing-petals about equal in length : pods about 4 mm. long, reticulate-wrinkled, 

 slightly pubescent. 



In waste places about cities, throughout the United States and southern British America. Natur- 

 alized from Europe and Asia. Spring to fall. 



3. Melilotus dlba Desv. Foliage glabrous, or twigs pubescent. Stems erect, 3-12 

 dm. tall, widely branching : leaflets 3, the blades linear-oolong, oblanceolate or ellip- 

 tic, 1-3 cm. long, obtuse or truncate at the apex or sometimes emarginate, serrate, longer 

 or shorter than the petiole : racemes wand-like, elongated : flowers often secund : calyx 

 campanulate, pubescent ; lobes usually shorter than the tube : corolla white, 4-5 mm. long ; 

 standard surpassing the wing-petals : pods oval, 3-3.5 mm. long, rugose, glabrous. 



In waste places about cities, throughout the United States and southern British America. Intro- 

 duced from Europe and Asia. Spring to fall. 



9. TRIFOLIUM L. 



Annual or perennial herbs, with erect or creeping stems. Leaves alternate : petioles 

 variable in length : blades digitately 3-foliolate or rarely 5-7-foliolate : leaflets entire or 

 toothed. Flowers perfect, disposed, in abbreviated or elongated racemes, often in heads. 

 Calyx pedicelled : lobes 5, slender, nearly equal, or broad and the upper 2 united. Corolla 

 of various colors, often white, pink or purple : standard straight or recurved : wings nar- 

 row, longer than the obtuse keel. Stamens 10, diadelphous (9 and 1) or the 10th filament 

 sometimes united to about the middle. Anthers all alike. Ovary sessile or stalked. 

 Ovules few. Pod flattish or terete, included in the persistent corolla. Seeds few or 

 solitary. CLOVER. 



Corolla yellow. 



Terminal leaflet longer-stalked than the rest. 



Racemes 8-12-flowered, much less than 1 cm. long. 1. T. dubium. 



Racemes 20-40-flowered. about 1 cm. long. 2. T. procumbens. 



Terminal leaflet not 1 longer-stalked than the rest. 3. T. agrarium. 



Corolla white, pink or purple. 



Flowers not reflexed at maturity. 



Racemes cylindric, peduncled : calyx plumose-pubescent. 4. T. arvense. 



Racemes subglobose, sessile : calyx glabrous or sparingly pubescent. 5. T. pratense. 



Flowers reflexed at maturity. 



Racemes over 2 cm. broad : cleistogamous flowers always wanting. 



Annual or biennial : foliage pubescent. 6. T. reflexum. 



Perennial : foliage glabrous. 7. T. stoloniferum. 



Racemes less than 2 cm. broad : cleistogamous flowers sometimes present. 

 Calyx nearly as long as the corolla. 



Calyx-lobes about as broad as long. 8. T. Bejariense. 



Calyx-lobes subulate. 9. T. Carolinianum. 



Calyx "barely % as long as the corolla. 

 Stems creeping. 



Racemes 6-12-flowered : creeping stems with cleistogamous flowers. 10. T. amphianthum. 

 Racemes many-flowered : cleistogamous flowers wanting. 



Leaflets prominently nerved, spinulose-serrate : terminal leaflet 



no longer stalked than the lateral. 11. T. saxicola. 



Leaflets not prominently nerved, serrulate : terminal leaflets 



longer stalked than the lateral. 12. T. repens. 



Stems erect or ascending. 13. T. hybridum. 



1. Trifolium dubium Sibth. Foliage glabrous, strigillose or pilose. Stems usually 

 branched at the base, the branches spreading or ascending, 0.3-5 dm. long : leaflets 3, the 

 blades cuneate to obovate, 4-8 mm. long, rounded, truncate or notched at the apex, dentic- 

 ulate, the terminal one longer-stalked than the rest : peduncles surpassing the subtending 

 leaves : heads rather loosely 8-12-flowered : calyx glabrous ; tube campanulate ; lobes lan- 

 ceolate or subulate-lanceolate, the longer surpassing the tube in length : corolla pale yellow 

 turning brown ; standard involutely folded, surpassing the wing-petals. 



In waste places and open grounds, New England to British Columbia, Florida and Texas. Natural- 

 ized from Europe. Spring and summer. 



2. Trifolium procumbens L. Foliage more or less densely pilose or strigillose. 

 Stems erect and simple or usually branched at the base, the branches decumbent or pros- 

 trate, 1-7 dm. long : leaflets 3, the blades cuneate or obovate, 6-12 mm. long, rounded or 

 notched at the apex, denticulate : racemes 20-40-flowered : peduncles surpassing the sub- 

 tending leaves : calyx usually sparingly pubescent ; tube campanulate ; lobes lanceolate or 



