LEGUMINOSAE 
53. 
14. 
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. 
PULSE FAMILY 
KEY TO GENERA 
Shrubs or small trees 
Fe opie: REPT TS. cn Suiata ek hey ohic,3linte toner As log Sh nen aces Zz 
MME ck adh es he oc Bile aoa oes adage eid ha tl epee a 
ae RS eee a sks ao eG Fx 9S ee Cercis p. 160 
eS Oe 5 re a Amorpha p. 165 
Deeemcemmir renGrns. 2 6. fay SEs eo oes et EE Vicia p. 172 
ESM RSE SERRE TCIUILUIS 1.5.8) 2s Sars. ss aio aoee oe we ae 4 
ements ee EM ns oye Pee 5 
ee een O MUR TEMIIAIA TS oo)... S's digas DEA nin OR * 
EL ee ig. a2 osc eS ho Ae Seas ee 6 
SE TRG ee ll oe ae Apios p. 173 
Leaflets more than 134 inches long, more than 1% inches 
A SR Se ee a ear ee er Phaseolus p. 173 
Leaflets not more than 1% inches long nor more than 
SI ES ae ee a Strophostyles p. 174 
EMM AIIMNE BUVECIE uno eh Bs 2s en» ae ow ee 8 
RemmonE rl bet I. WiHteG: . .. 2. del.c.> - wins ee » Re 9 
oS SE ee See eee en eee Baptisia p. 161 
phe ES eta eo Ae ie ee een cnn erg Cassia p. 158 
Four of the petals attached to stamen tube. Petalostemum p. 166 
Nerperals attached to stamen tube.. 2... 22-0... 47-theee fe) 
eR ee oan a ee a aa > oon eee Bee II 
Me CememrMRC EMA B. bidsae ni be ads £ os ese See pee Paweagay 13 
Flowers yellow or white in slender racemes... . Melilotus p. 163 
Flowers yellow in dense heads......Medicago in part p. 163 
JEU SLT @ DEE Seas 2 5: rr er ernie Zs ie IRS, i) 
Ovule or seed 1; pod not jointed......-..—<.. Psoralea p. 164 
Ovules or seeds 2 or more; pod jointed......Desmodium p. 170 
Ree en eee be 3 Sos oe ae See ee Lupinus p. 162 
Pare iASe wo Sot etwas a neo ame ae 14 
Plant densely covered with silky, whitish hairs....... ace 
te cet. ers SESE SS saRuay.. oYEeR Tephrosia p. 168 
faset smooth or-nearly so: 26...) 2.6. 2 2s es Astragalus p. 169 
