8 



AGRICULTURAL VARIETIES OF THE COWPEA, ETC. 



Mr. George W. Oliver, and it is not improbable that some or all of 

 the forms connecting these species may, in fact, be hybrids. 



The most ancient cultivation of the vignas seems to have been in 

 India and to have spread in prehistoric times to China, the whole 

 of the Malayan region, and probably much of Africa. It was known 

 in southern Europe at least as early as the beginning of the Chris- 

 tian Era. 1 As might be anticipated, varieties received from different 

 sources are in the main distinct, even if the differences in many cases 

 are slight. The very long cultivation of the cowpea in Africa is 

 attested by the fact that the varieties from different parts of that 

 continent are with few exceptions distinct from those grown else- 

 where. 



The numerous varieties of cowpeas that have become established 

 in America during the past hundred years probably came, in part at 

 least, either from India or China, as the black-eyed and brown-eyed 

 varieties are, and probably always have been, practically the only 

 ones cultivated in southern Europe. 2 In regard to some of the more 

 important varieties, special data will be found in connection with 

 their descriptions. 



Notwithstanding the great difficulty in defining clearly the three 

 supposed species, each, nevertheless, represents a group of varieties 

 having much in common. For the present purposes the species may 

 be contrasted as follows: 



Vigna sesquipedalis. — Seeds elongated kidney form, 8 to 12 mm. 

 long, their thickness much less than their breadth ; pods pendent, 

 much elongated, 1 to 3 feet long, fleshy and brittle, becoming more 

 or less inflated, flabby, and pale in color before ripening, and shrink- 

 ing about the widely separated seeds when dry. 



Vigna catjang. — Seeds small, usually oblong or cylindric and but 

 slightly kidney shaped, 5 to 6 mm. long, nearly or quite as thick as 

 broad; pods small, not at all flabby or inflated when green, mostly 

 3 to 5 inches long, erect or ascending when green, remaining so when 

 dry or at length becoming spreading or even deflexed. 



Vigna unguiculata. — Seeds mostly 6 to 9 mm. long, varying from 

 subrenif orm to subglobose ; pods 8 to 12 inches long, early becoming 

 pendent, not at all flabby or inflated when green. 



As thus defined the great majority of the varieties classify readily 

 into one of the three species. In each species there is a wide range 

 of closely similar seed colors, greatest in Vigna unguiculata, least 

 in V. sesquipedalis. The small seeds and erect or semierect pods of 

 the catjangs are seemingly correlated characters, the erectness of the 

 pods apparently being due in large measure to their relatively small 



1 Compare Wight, W. F., Bulletin 102. Bureau of Plant Industry, U. S. Dept. of 

 Agriculture, 1907. 



2 Compare notes given under Dolichos monachalis, p. 11. 



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