DISTINCTIVE CHARACTERS OF COWPEA VARIETIES. 



23 



having only the buff ground color left. Much additional work is 

 necessary to determine all these points with certainty. 



The colors of the seeds as here given are based on fresh, uninjured 

 seeds. Old seeds become much darker, so that buff, pink, and maroon 

 finally may become indistinguishable. Where the ripe pods have 

 been frequently wet by rains and covered with black mold, the seed- 

 also become discolored, usually yellowish or brownish. The termi- 

 noloffv used for the colors is based on Ridgway's Nomenclature of 

 Colors. 



Shape. — Cowpea seeds may be conveniently if not very clearly put 

 into five categories as to shape — reniform or kidney shaped, sub- 

 reniform. oblong, rhomboid, and globose. In some varieties the 

 whole seed is rounded and plump, in others the sides may be shrunken 

 so that the back of the seed is more or less conspicuously " keeled." 

 The seed coat is usually smooth, but often transversely and finely 

 wrinkled, especially in white or nearly white seeds. As both smooth 

 and wrinkled seeds may occur in the same pod, the character has 

 little distinctive value except in a few cases. 



The shape of the seed is closely correlated with that of the pod. 

 Where the seeds are separate from each other while developing they 

 are invariably reniform or subreniform, more elongated or less in 

 proportion to the distance they are apart. Where the seeds touch 

 each other while growing, flattened ends and usually a more oblong 

 shape result. If the seeds are crowded so closely that they become 

 cuboid or rhomboid, such varieties are designated as " half crowders." 

 Where the seeds are closely crowded while developing they become 

 when mature either globose or compressed. Such pods and varieties 

 are called " crowders." Crowder pods are commonly cylindric in 

 form or else broader than they are thick, and the pod is usually of 

 rather thick and brittle texture. It must be borne in mind that the 

 seeds are largest just before they mature and it is the pressure at this 

 time that in the main determines their form; hence, considerable 

 variation in the shape of seeds may be noted even in the same pod. 

 depending on the position in the pod and the amount of pressure 

 experienced. 



Size. — The size of the seeds from the smallest catjangs on the one 

 hand to the Taylor variety, the largest extreme on the other, is well 

 shown in the illustrations. To some extent these also show the vari- 

 ation in size in each variety. This variation may be considerable 

 even in different pods on the same plant. The latest formed and 

 therefore half -starved pods are often undersized, with correspond- 

 ingly small seeds. 



PODS. 



The general interrelations of seeds to pods have been already 

 described. The shape of the pod is usually curved or falcate. In 



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