LEGUMINOSAE PULSE FAMILY 



The Pulse family is extremely important to man. The 

 Bean, Pea and Peanut are used as human food, Clover and 

 Alfalfa are forage crops, and the Sweet Pea is highly prized 

 as a garden flower. 



Still more important, however, is the fact that on the roots 

 of all members of the family are little tubercles inhabited by 

 bacteria; these bacteria are capable of taking nitrogen from 

 the air and combining it with other elements so that it may 

 be used by plants for constructing protein foods. Wherever 

 these plants grow, therefore, the amount of available nitrogen 

 in the soil is increased, and on this account all crop rotations 

 are planned to include a member of the Pulse family every 

 three or four years. 



Flowers cf the genera Cercis, Amorpha, Cassia and Petal- 

 ostemum do not have butterfly-shaped corollas. 



KEY TO GENERA 



Shrubs or small trees 2 



Herbs 3 



Leaves simple Cercis p. 1 60 



Leaves compound Amorpha p. 165 



Leaves with tendrils Vicia p. 172 



Leaves without tendrils 4 



Climbing plants 5 



Plants not climbing 7 



Leaflets 3 6 



Leaflets 5-19 Apios p. 173 



Leaflets more than li^ inches long, more than i}4 inches 



wide Phaseolus p. 1 73 



Leaflets not more than i]A inches long nor more than 



I inch wide Strophostyles p. 174 



Stamens not united 8 



Stamens, or all but i, united 9 



Leaflets 3 Baptisia p. 161 



Leaflets more than 3 Cassia p. 1 58 



Four of the petals attached to stamen twht . Petalosternitm p. 166 

 No petals attached to stamen tube 10 



10. Leaflets 3 11 



Leaflets more than 3 13 



11. Flowers yellow or white in slender racemes. . . .Melilotiis p. 163 



Flowers yellow in dense heads Medicago in part p. 163 



Flowers purple or pinkish 12 



12. Ovule or seed i ; pod not jointed Psoralea p. 164 



Ovules or seeds 2 or more; pod jointed Desmodium p. 170 



13. Leaves palmate Lnpinus p. 162 



Leaves pinnate 14 



14. Plant densely covered with silky, whitish hairs 



Tephrosia p. 1 68 



Plant smooth or nearly so Astragalus p. 169 



157 



