PULSE FAMILY 135 



2. M. officinalis Willd. YELLOW SWEET CLOVER. A stout, upright, 

 branching herb, 2-4 ft. high, looking much like the preceding species, 

 but coarser. Flowers yellow. Waste ground and roadsides. Natu- 

 ralized from Europe. 



XIV. MEDICAGO L. 



Annual or perennial herbs. Leaves petioled, of 3 toothed 

 leaflets. Flowers in terminal and axillary spikes or racemes. 

 Calyx 5-toothed, the teeth short and slender. Standard 

 oblong, much longer than the wings or keel. Stamens 10, 

 diadelphous. Ovary sessile. Pod 1 -several-seeded, coiled, 

 not splitting open, often spiny.* 



1. M. sativa L. ALFALFA. Perennial. Stems erect, branching, 

 downy when young, becoming smooth with age, 2-3 ft. high. Leaves 

 short-petioled ; leaflets obovate, sharply dentate towards the apex, 

 obtuse or sometimes notched or mucronate ; stipules lanceolate, entire. 

 Flowers blue, small, in rather close spikes. Pods downy, coiled, few- 

 seeded. Introduced from Europe, and cultivated for hay and pasture.* 



2. M. lupulina L. BLACK MEDICK, NONESUCH. An annual or 

 biennial, much-branched, reclining herb, with stems 6-20 in. long. 

 Leaves very short-petioled ; leaflets obovate, acute, -f in. long, toothed 

 near the tip. Flowers small, yellow, in short spikes. Pods very small, 

 1-seeded, kidney-shaped, black. Roadsides and waste ground, adven- 

 tive from Europe. 



XV. PSORALEA L. 



Perennial herbs ; whole plant glandular-dotted. Leaves of 

 3-5 leaflets ; stipules united with the petioles. Flowers in axil- 

 lary or terminal spikes or racemes. Calyx 5-cleft, the lobes 

 nearly equal. Standard ovate or orbicular ; keel incurved, 

 obtuse. Stamens monadelphous or diadelphous, 5 of the anthers 

 often undeveloped. Ovary nearly sessile. Pod included in the 

 calyx, often wrinkled, remaining closed, 1-seeded.* 



1. P. pedunculata Vail. SAMSON'S SNAKEROOT. Stem erect, slen- 

 der, branching above, downy, 1-2 ft. high. Leaves of 3 leaflets ; 

 petioles shorter than the leaflets ; stipules awl-shaped ; leaflets ellip- 

 tical or oblong-lanceolate, sparingly glandular-dotted, the terminal 

 one stalked. Loosely flowered spikes axillary and terminal, on pedun- 

 cles much longer than the leaves. Flowers blue or purple, about ^ in. 

 long. Pod compressed-globose, wrinkled transversely. Dry soil.* 



2. P. tenuiflora Pursh. Upright, slender, bushy and branching, 

 2-4 ft. high, covered when young with a fine grayish down. Leaves 



