42 KEY TO THE SPECIES 



8. MEDICAGO (Medick) 



Herbs with pinnatel; 3-toliolate leaves, toothed leaflets, flowers nearly as in 

 Melilotus, but the pod curved or variously coiled. 



1. Medicago sativa L. (Lucerne, Alfalfa). Upright and smooth ; leaflets 

 obovate-oblong, toothed ; purple flowers in racemes ; pods spirally twisted. Cul- 

 tivated for fodder ; from Europe. 



4. MELILOTUS (Sweet Clovee) 



Herbs (fragrant in drying) with pinnately 3-foliolate leaves, toothed leaflets, 

 flowers much as in Trifolium but in long racemes, and ovoid tough and wrinkled 

 pods. 



1. Melilotus offlcinalis (L.) Lam. (Yellow Mblilot). Upright, 2-4 ft. high ; 

 leaflets obovate-oblong, obtuse : flowers yellow. Waste or cultivated ground ; 

 from Europe. 



2. Melilotus alba Desv. (White Melilot). Leaves truncate ; flowers white. 

 Waste or cultivated ground ; from Europe. 



5. TRIFOLIUM (Cloter) 



Tufted or spreading herbs with palmately 3-foliolate leaves, usually toothed 

 leaflets, small flowers in heads or spikes, a 5-cleft calyx with bristle-like teeth, a 

 short and obtuse keel, and a small membranous pod. 



• Introduced ; in cultivation and escaped along roadsides and ditch-banks. 



1. Trifolium pratense L. (Red Clover). Stemsascending, somewhat hairy; 

 leaflets oval or obovate, often notched at tip and with a pale spot above ; rose- 

 purple flowers sessile in dense ovate heads, the corolla elongated-tubular. 

 Meadows and largely cultivated ; from Europe! 



2. Trifolium repens L. (White Clover). Stems slender, smooth, spreading 

 and creeping ; leaflets inversely heart-shaped or only notched, obscurely toothed ; 

 flowers on stalks in small and loose umbel-like heads, reflexed when old ; calyx 

 much shorter than the white corolla. Fields, lawns, and roadsides. 



* * Native. 



3. Trifolium anemopliilum Greene (Eock Clover). Low, densely caespi- 

 tose, silvery or cinerously canescent, nearly stemless ; leaflets linear-oblong, taper- 

 ing to both ends ; stipules scarious ; involucre of several, unequal, scarious green- 

 ribbed segments ; calyx purplish, with unequal, linear teeth ; corolla uniformly 

 purple ; styles as long as the few-seeded pod. Occurring mostly on naked stony 

 slopes and in rocky ravines. 



4. Trifolium Parryi Gray (Parry's Clover). Low, glabrous and stoutish ; 

 leaflets oblong-oblanceolate, sharply dentate ; bracts 5-7, oblong, obtuse ; flowers 

 purple, 20 or more in a rather large head. In open coniferous woods at sub-alpine 

 stations. 



6. PETALOSTEMON (Prairie-clover) 



Perennial herbs, sometimes with woody base ; leaves glandular-punctate and 

 the flowers spieate. Calyx teeth nearly equal ; petals clawed, the cordate standard 

 free, the claw of the wing and keel petals attached to the stamen tube. 



1. Petalostemon oligopliyllus (Torr.) Rydb. (Slender Prairie-clover). 

 Stems several from the woody caudex, spreading, 2-4 cm. long ; leaflets 5-9, nearly 



