272 



PAPIUONACEAE. 



Perennial; flowers violet, conspicuous; 

 Annual; flowers bright yellow, small. 



Pod i -seeded, curved, not spiny. 



Pod several-seeded, spiny on the edges, spirally twisted. 



Pod loosely coiled, not furrowed on the edge. 



Pod densely coiled, its edge furrowed. 



[Vol.. II. 



1. M. saliva. 



2. M. lupulina. 



3. M. denticulata. 



4. M. Arabica. 



i. Medicago sativa I,. Purple Medic. Alfalfa. 



Lucerne. Burgundy, Chilian or Brazilian 



Clover. Snail Clover. (Fig. 2064.) 



Medicago saliva I,. Sp. PI. 778. 1753. 



Perennial, much branched, decumbent or ascending, 

 i-i% high, the young shoots and leaves with some 

 scattered hairs, glabrous when mature. Leaves pe- 

 tioled; leaflets oblanceolate or obovate, 2 // -i2 // long, 

 dentate, especially toward the apex, obtuse, truncate 

 or emarginate and often mucronate, narrowed or cun- 

 eate at the base; stipules entire; peduncles )4'-2' long, 

 bearing a dense short raceme of violet or blue flowers; 

 petals about 3" long; pod pubescent, twisted into 2 or 

 3 spires. 



In fields and waste places, New England and Ontario to 

 Minnesota, south to Virginia and Missouri. Much culti- 

 vated for fodder in the southern and western States. Intro- 

 duced from Europe. Great or Spanish Trefoil. Summer. 



2. Medicago lupulina L. Black or Hop Medic. 



Blackseed Hop Clover. Nonesuch. 



(Fig. 2065.) 



Medicago lupulina L. Sp. PI. 779. 1753. 



Annual, pubescent, branched at the base, the branches 

 decumbent and spreading, often i-2 long; leaves pe- 

 tioled; leaflets obovate, oval or nearly orbicular, variable 

 in size, sometimes 6"-8" long, denticulate or crenulate, 

 obtuse, mucronate or emarginate, narrowed or rounded 

 at the base; stipules ovate or^lanccolatc, dentate; pedun- 

 cles i '-3' long; head oblong 'or cylindric, dense, 2"-io" 

 long; flowers bright yellow, about \" long; pods nearly 

 glabrous, black when ripe, curved into a partial spire, 

 strongly veined, i -seeded. 



In fields and waste places, common throughout our area, 

 and widely distributed as a weed in all temperate regions. 

 Native of Europe and Asia. Called also Black or Melilot 

 Trefoil, Black-grass, and sometimes Shamrock. March-Dec. 



3. Medicago denticulata Willd. 

 Toothed Medic. (Fig. 2066.) 



Medicago denticulata Willd. Sp. PI. 3: 1414. 1803. 

 Annual, branched at the base, the branches 

 spreading or ascending, glabrous or with a few 

 apprcssed hairs. Leaves petioled; leaflets ob- 

 ovate, rounded, emarginate or obcordate, cune- 

 ate, crenulate, 5"-8" long; stipules dentate; 

 flowers few, yellow, i // loug, in small, peduncled 

 heads; pod several seeded, spirally twisted, the 

 2 or 3 coils flat and rather loose, elegantly reticu- 

 lated with elevated veins, the edges armed with 

 i or 2 rows of curved prickles and not furrowed 

 between them. 



In waste places and in ballast about the seaports, 

 Nova Scotia to Pennsylvania; also in the southern 

 and western States and on the Pacific Coast. Fugi- 

 tive or adventive from Europe. Native also of 

 Asia and widely distributed as a weed. Summer. 



