20 AGRICULTURAL VARIETIES OF THE COWPEA, ETC. 



series. The most important characteristics from an agronomic stand- 

 point are height, vigor, and prolificness. Practically all of the really 

 valuable varieties fall in groups 3, 4, and 5, the very best being in 

 group 4. The ideal habit for field use would seem to be exhibited by 

 the more vigorous arborescent varieties, such as catjangs Xos. 21292, 

 21602, and 22759, but unfortunately the best of these are very late 

 and, under American conditions at least, not prolific. The procum- 

 bent and prostrate varieties are of little value except for use as pas- 

 ture or as a cover crop. It would seem highly improbable that the 

 seed of any of these last could ever be grown cheaply enough to com- 

 pete with the half-bushy varieties, notwithstanding that several of 

 the procumbent sorts, such as Xo. 21006, are the most vigorous 

 growers of all. 



There is often marked difference in the appearance of plants grow- 

 ing isolated and those of the same variety when more or less crowded. 

 This is especially marked in the half-bushy varieties. In these the 

 basal branches grow inordinately when the plants are isolated so that 

 the result is a procumbent mass. On the contrary, when the plants 

 are grown close together the development of the basal branches is 

 usually much inhibited and the main stem is correspondingly taller 

 so that the plants are much more bushlike in habit. In the varieties 

 that are normally procumbent or prostrate this effect is much less 

 marked, as the vines of such varieties are seldom stiff enough to hold 

 up. The few truly upright (arborescent) varieties, which have no 

 trailing basal branches, seem to maintain this character whether 

 growing isolated or close together. 



STEMS. 



The stem possesses very few characters which are of value as dis- 

 tinguishing marks. Such differences in stoutness as exist may be 

 characterized by the terms coarse, medium, and fine. The color of the 

 stems is correlated with that of the leaves. Thus, pale stems are 

 associated with pale leaves and purple stems with purple leaves, but 

 the stem may show all degrees in the extent of purple color. The 

 coloring is most common at the nodes and on the peduncles. A small 

 amount of purple in the stems may or may not be associated with 

 purple coloration in the leaves even in the same variety. The first 

 cold nights of autumn not only cause an increase in the amount of 

 purple coloration but also cause it to appear in varieties where it was 

 not before evident, especially on young pods. 



LEAVES. 



Economically, the most important leaf character is the ability to 

 persist on the vines till the pods are mature. This is very character- 

 istic of the Iron variety. Other characters observable but difficult 



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