604 FABACEAE 



7. MEDICAGO L. 



Herbs or shrubby plants, with erect or prostrate stems. Leaves alternate : blades 

 pinnately 3-foliolate : leaflets commonly toothed by the prominent excurrent lateral nerves. 

 Flowers perfect, in elongated or head-like ped uncled racemes. Calyx pedicel led : lobes 

 slender, nearly equal. Corolla yellow or violet : standard with an oblong or obovate 

 nearly sessile blade : wings nearly oblong : keel obtuse, shorter than the wings. Stamens 

 10, diadelphous, the one opposite the standard, distinct. Anthers all alike. Ovary sessile 

 or short-stalked. Style subulate. Stigma oblique. Ovules numerous or rarely solitary. 

 Pod curved or spirally coiled, often spiny, usually reticulated, indehiscent. MEDIC. 



Pods unarmed, 1-seeded. 1. M. lupulina. 

 Pods prickle-armed, several-seeded. 



Pods loosely coiled, not furrowed on the edge between the prickles. 2. M. dcnticulata. 



Pods tightly coiled, furrowed on the edge between the prickles. 3. M. Arabica. 



1. Medicago lupulina L. Foliage strigillose. Stems branching at the base, the 

 branches spreading, prostrate, 2-7 cm. long ; leaflets 3, the blades obovate or rhomboidal, 

 0.5-1.5 cm. long, usually retuse and mucronate at the apex, denticulate, sessile or short- 

 stalked : petioles variable in length : peduncles slender, 2-10 cm. long : racemes subglobose 

 or ovoid in flower, oblong-cylindric in fruit : calyx-tube turbinate : corolla bright yellow, 

 2-3 mm. long : pods spirally twisted, about 3 mm. long, black, reticulated, glabrous or 

 nearly so, unarmed, 1 -seeded. 



In waste places throughout North America except the extreme north. Spring to winter. Widely 

 naturalized in temperate regions, from Europe and Asia. 



2. Medicago denticulata Willd. Foliage glabrous or sparingly pubescent. Stems 

 branched at the base, the branches radially spreading, ascending or procumbent, 1-4 dm. 

 long : leaflets 3, the blades obovate, cuneate or oval, 0.5-1.5 cm. long, denticulate, rounded, 

 retuse or notched at the apex : petioles variable in length: peduncles 0.5-2 cm. long: 

 calyx often sparingly pubescent : corolla yellow, about 5 mm. long : pods loosely twisted 

 into 2-3 coils, flat, 5-8 mm. broad, reticulated, the edges armed with 1-2 rows of curved 

 prickles. 



In waste places, especially near seaports, Nova Scotia to Florida and Texas. Summer. Naturalized 

 from Europe and Asia. 



3. Medicago Arabica All. Foliage glabrous or pubescent with a few spreading 

 hairs. Stems branched at the base, the branches prostrate or ascending : leaflets 3, the 

 blades broadly cuneate or obovate, 1-2.5 cm. long, denticulate, usually blotched in the 

 center, rounded or notched at the apex : petioles commonly longer than the leaflets : 

 peduncles 1-2 cm. long : calyx often sparingly pubescent : corolla yellow, about 5 mm. 

 long : pods closely twisted into 3-4 coils, 6-9 mm. broad, reticulated, the edges armed 

 with curved prickles. 



In waste places, New Brunswick to Georgia and Louisiana. Summer. Introduced from Europe. 



8. MELILOTUS Juss. 



Annual or biennial caulescent herbs, with fragrant herbage. Leaves alternate, with thin 

 stipules : blades pinnately 3-foliolate : leaflets much longer than broad, the nerves excur- 

 rent into teeth. Flowers perfect, in elongated narrow racemes. Calyx pedicelled : 

 lobes 5, nearly equal. Corolla yellow or white, deciduous : petals free from the filaments : 

 standard rather abruptly contracted at the base of the blade, nearly sessile : wings narrower 

 than the standard, cohering with the shorter obtuse keel-petals. Stamens diadelphous. 

 Ovary sessile or short-stalked. Style filiform. Stigma terminal. Ovules few. Pod 

 straight, short and thick, often subglobose, indehiscent or nearly so. SWEET CLOVER. 



Corolla 2-2.5 mm. long. 1. M. Indica. 

 Corolla 5-6 mm. long. 



Corolla yellow : standard and wing-petals about equal in length. 2. M. officinalis. 



Corolla white : standard surpassing the wing petals. 3. M. alba. 



1. Melilotus Indica (L. ) All. Foliage minutely pubescent when young. Stems 

 erect or spreading, 2-7 dm. long, sometimes copiously branched : leaflets 3, the blades ob- 

 long, oval, cuneate or obovate, 0.5-2 cm. long, retuse to rounded at the apex, serrate : 

 racemes slender, 1-2 cm. long : calyx campanulate ; lobes longer or shorter than the tube 

 which is scarious in the sinuses : corolla yellow, about 2-2.5 mm. long ; standard with a 

 blade 1-1.5 mm. broad : pods oval or subglobose, 2 mm. long, wrinkled. 



In waste places, about seaports, on the Atlantic and Pacific coasts and sometimes in the interior. 

 Introduced from Europe. Spring to fall. 



