ORIGIN OF THE CULTIVATED LEGUMES 259 
2. Trifolium medium, the mammoth, giant, or pea-vine clover, 
similar to the above, but with a growth so heavy that the stems 
no longer stand erect but lie creeping on the ground. 
3. Trifolium repens, the common white or Dutch clover, grow- 
ing wild in pastures everywhere in the northern United States 
and never cultivated. 
4. Trifolium hybridum, the common alsike, similar to the 
above only larger, with a stronger stem and a touch of pink in 
the blossom, grown freely on moist ground for hay. 
5. Infolium incarnatum, the crimson or Italian clover; a 
short erect species with a long, beautiful scarlet “ head,”’ mak- 
ing a small quantity of good hay but rarely used by American 
farmers, as the yield is low. 
These clovers are all leguminous plants and all serve the 
same purpose as soil restorers so far as nitrogen is concerned. 
The farmers’ choice therefore turns on the question of yield 
and general usefulness. 
This rules out white clover as a cultivated crop, but it has no 
difficulty in maintaining itself as a wild plant,! to the great ad- 
vantage of our self-sown native pastures. 
The scarlet clover is but recently introduced into cultivation. 
According to Candolle it exists wild in Gallicia, in Biscaya and 
Catalonia, as also in Sardinia, in Algiers, and in the valley of the 
Danube, in some of which places it may have been introduced 
since cultivation. It is surely indigenous in the neighborhood 
of the Pyrenees and also along the coast of Cornwall, where it 
is associated with a yellow variety which is truly wild also on 
the continent.” 
This shows how the process of domestication is sometimes 
long deferred, and may even be abandoned if, after trial, the 
species is not found worthy, as will more than likely be the 
case with this particular clover. 
1 In this respect it rivals Kentucky blue grass, with which it is often asso- 
ciated, an association clearly advantageous to the blue grass, whose supply of 
nitrogen is thereby better assured. 2“ Origin of Cultivated Plants,” p. 106. 
