24 KANSAS UNIVERSITY SCIENCE BULLETIN. 



lination. At the present, the most logical explanation to be 

 suggested seems to be that, when the flowers partially close at 

 night, the tips of the pistil and the large stamen are brought 

 into contact. This might occasionally occur, but it is by no 

 means always the case. At the time of the writing of this pa- 

 per, material for the determination of this point is not available, 

 but two or three flowers examined at night during the summer, 

 before the results of the above experiments had suggested the 

 importance of a careful examination of a large series of material, 

 did not show the stamen and pistil in contact. Of course, note 

 will be taken of the fact that in only one out of thirteen flowers 

 on the plant did spontaneous pollination take place. Another 

 suggestion might be that, approaching so near as they do to 

 each other, a puff of pollen might be thrown from the large 

 stamen and fall upon the pistil when the plant is shaken. 



In plants I and II, it will be seen that, in the first case, three 

 fully developed seed pods were obtained from twelve flowers 

 the stigmas of which were supplied with pollen from the large 

 stamen of the same flower. In the second case, one fully de- 

 veloped seed pod was obtained from four pollinated flowers — 

 just twenty-five per cent, in each case. 



In the cases in which cross-pollination was effected between 

 right- and left-handed flowers opening simultaneously on the 

 same raceme, we find that, in the first, one pod of the two was 

 only half developed at the end of twenty days. Since the pods 

 are normally fully developed in somewhat less than this length 

 of time, and this undeveloped pod appears somewhat dried, its 

 development seems doubtful. In the second case, one pair of 

 seed pods out of seven pairs of flowers crossed were fully de- 

 veloped, and one seed pod from each of two other pairs were 

 fully and normally developed, making four out of fourteen 

 flowers which yielded seed pods — 28.5 per cent. 



Professor Todd observed only a small humblebee visiting 

 the flowers of this plant. Owing, probably, to more favorable 

 opportunities for observation, the writers have been able to se- 

 cure other insects collecting pollen. 



The following is a list of the species : 



Agapostemon texanvs Cress. Two specimens collected August 

 5, at two p. m. The insects were collecting pollen from the 

 small stamens, to which they clung while they forced the pollen 



