462 BOTANY OF CROP PLANTS 



Environmental Relations. — The cowpea is of tropical 

 origin, and, hence, is adapted to those sections of the country 

 with warm summers; in fact, it requires more heat than 

 com, and like corn, does not thrive where the nights are cool. 

 It is seldom grown north of the Ohio River. It will grow on 

 many different soil types, and will withstand shading. 



Uses.- — The cowpea is of very great economic importance. 

 It is the chief forage plant in the South Central and South 

 Atlantic States. The acreage of the crop is increasing each 

 year. Cowpea hay is prized as food for stock. The plant 

 may also be pastured with hogs or sheep when mature, or 

 with cattle before the peas mature. The plant is being 

 introduced into many localities as a catch crop or as a green 

 manure, and is adapted to rotation in a cropping system. 

 The seeds are fed to poultry, and are also recommended as 

 a food for man. The roasted seeds are a substitute for 

 coffee. 



ASACmS HYPOGCEA (Peanut, Goober) 



Habit, Stem. — The peanut is an annual plant with a tap 

 root (Fig. 196). The plant may be low and prostrate, as in 

 the "running types," or upright and bushy, as in the "bush 

 t3T)es." The stems are thick, angular, branching, and hairy. 



Leaves. — The leaves are pinnately compound, usually 

 with two pairs of subsessile, entire leaflets, and no tendrils; 

 the elongated stipules are adnate to the petiole base. 



Flowers (Fig. 197). — The flowers are axillary, sessile, 

 and orange-yellow in color. There are two sorts of flowers 

 on the plant, sterile and fertile. Sterile flowers are most 

 numerous in the upper axils, on long, slender pedicels; they 

 have monadelphous stamens (nine united, one abortive) 

 and a minute abortive ovary. The calyx tube is long and 

 slender, and bears on its rim the calyx lobes, corolla, and 



