138 NATURE STUDY AND AGRICULTURE 
used for the purpose. It has a longer taproot than any other 
farm crop and is a great resister of drought and heat as 
well as cold. 
Sweet Clover has long been familiar as a roadside weed, 
but recently the variety with white blossoms has become 
popular in the Northwest for stock 
feeding. It begins growing very 
early in the spring, and when young 
furnishes excellent pasturage. At 
least one crop of hay may be cut 
from it the first season after plant- 
ing and two or three the second 
season. Then the roots die, as the 
plant is a biennial. It should be 
cut before it commences to blossom 
or it will become too tough and 
woody. Sweet clover will make a 
good growth on soil that will 
scarcely sustain other vegetation, 
and it survives the severest climatic 
conditions. 
Native or Wild Legumes. — There 
are growing on the unbroken prai- 
ries of the Northwest 30 or 40 species 
of legumes that have no doubt con- 
tributed much to the fertility of the 
virgin soil. The large majority of them, however, are too 
hard and tough to be eaten by stock ; a few are quite valuable. 
Special mention should be made of the American vetch, 
which grows in fairly damp ground; the wild vetch or prairie 
bird’s-foot trefoil, an annual plant growing especially in dry 
or sandy soil; the marsh vetchling, growing among the grasses 
TaN 
WHITE SWEET CLOVER 
