VARIABILITY OF THE COWPEA. 



15 



It is doubtful if any of the very late varieties of cowpeas, which 

 means those that require, under American conditions at least, 120 

 days to mature their first pods, will find a place in our agriculture. 

 According to Prof. P. H. Rolfs, a very late cowpea that could be 

 planted in May and would not mature until late September would 

 be desirable in Florida, as it would shade the ground during the 

 summer and mature at the best season for curing hay. A large num- 

 ber of very late varieties were tested in Florida in 1909 with this 

 end in view, but none proved satisfactory, and it seems probable 

 that other legumes will meet the need much better than cowpeas. 



VARIABILITY OF THE COWPEA. 



Under different conditions of soil or climate most varieties of the 

 cowpea exhibit marked fluctuating variations. On rich soil, or when 

 planted early, the general tendency is to produce a large amount of 

 vine and but few pods. Unusually moist seasons seem to have the 

 same effect. On poor and especially on sandy soils, or when sown 

 late, the plants tend to be much more prolific of seed and to produce 

 decidedly less herbage. Moderate drought has a very similar effect. 

 Very severe drought, however, prevents most varieties from producing 

 pods. Thus, at Chillicothe, Tex., in 1910, the drought was so severe 

 that such varieties as Whippoorwill, Brabham, Groit, Iron, and 

 others produced scarcely a pod, though making fair vegetative 

 growth. In marked contrast, Blackeye No. 22050 produced a good 

 crop of pods. A number of varieties, like New Era and Whippoor- 

 will and to a less extent Iron, are half bushy when grown thickly. 

 When grown isolated, all these will produce long, trailing branches 

 and be decidedly decumbent ; when planted in corn their vining char- 

 acter is accentuated. These fluctuating variations are so marked, 

 the number of varieties of cowpea so large, and the seed so often 

 mixed that the idea has not unnaturally arisen that the cowpea is in 

 an almost continuous state of change, new varieties arising constantly, 

 many of them not permanent. This idea has been upheld by a num- 

 ber of writers on cowpeas, but in no case has satisfactory evidence of 

 its truth been advanced. 



A few varieties, such as Whippoorwill, New Era, Iron, and 

 others, have been well known for at least a decade. If these were 

 constantly varying, we should expect that seeds from different 

 sources would yield different looking plants. To test this, seeds 

 of Whippoorwill were obtained from the following different sources : 

 Richmond, Ya. ; Fayetteville, Ark. ; Hickory, N. C. ; Xewbern, K C. ; 

 Felton, Del. : Memphis, Tenn. ; Blodgett, Mo. ; and Coulterville, 111. 

 These seeds were planted in 1908 at Arlington Farm and grown in 

 comparison with a strain of the same variety that has been grown 



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