32 



AGRICULTURAL VARIETIES OF THE COWPEA, ETC. 



0618. Seeds colored like Watson. This cross produced in 1908 Blackeye and 

 Watson. The Blackeye bred true in 1909, while the Watson produced Black as 

 well as Watson. 



0625. A small black Crowder with buff spots bavin? Taylor specks. After 

 growing two seasons, the progeny of this contains Lady. Blackeyed Lady. Black, 

 purple black, medium-sized purple Crowder with Taylor markings, Taylor-eyed 

 Lady, that is, like Blackeyed Lady with the Taylor color about the eye and 

 seeds like the parent form. 



0626. A small black Crowder. Has yielded for two years a black Crowder, 

 Lady, and Blackeyed Lady. 



The above examples show beyond doubt the fact that these peculiar 

 seeds were really mixed breeds containing the blood of two or more 

 varieties. That they originated spontaneously as stated by Mr. 

 Trinkle is scarcely to be questioned. 



An interesting problem is presented in determining why cowpeas 

 cross so freely at Madison. Ind., while apparently never or at least 

 very rarely interbreeding at Arlington Farm and elsewhere. There 

 is nothing in the structure of the cowpea flower to prevent natural 

 crossing by large insects such as bumblebees. While most insects are 

 attracted to cowpeas to obtain honey from the extra-floral nectaries 

 outside the base of the flowers, nevertheless there is also a small 

 quantity of honey at the base of the flower inside, which can be 

 reached by butterflies and long-tongued bees. At Arlington Farm 

 butterflies obtain the honey without extruding the stigmas. But 

 few bumblebees were observed on the flowers at Arlington during 

 1909, though a number of flowers were found from which the column 

 protruded. Very slight pressure, about equal to that exerted by a 

 large bumblebee in obtaining the nectar, will cause the column to 

 protrude and frequently remain protruding. In such case the stigma 

 and hairy part of the style would rub against the underside of the 

 insect, and if the insect had previously visited other cowpea flowers, 

 it seems exceedingly probable that a natural cross would be brought 

 about in this way. 



This was also Mr. Trinkle's opinion, as he writes under date of 

 April 1; 1907: 



I believe the bumblebee is responsible for the crossing, as I have noticed that 

 it is strong enough and does sometimes opeu the corolla to get at the nectar, and 

 this exposes the pistil. 



Again he writes under date of August 7, 1909 : 



I notice a great number of bumblebees in my field working over the cowpea 

 blooms and that occasionally a flower may be seen with its reproductive or- 

 gans exposed, so that the bees come in contact with them. I have not noticed 

 any other insects on the blossoms. 



The only other place that has come to our attention where such in- 

 discriminate crossing takes place is at the Michigan Agricultural 

 College, where the crossing of the cowpeas has been under observa- 



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