28 KANSAS UNIVERSITY SCIENCE BULLETIN. 



The lower stamens and the pistil of the Solarium under con- 

 sideration serve the purpose of a platform when the flowers are 

 visited by the larger bees. It seems to the writers that this is 

 not improbably the function of the greatest importance of the 

 observed arrangements of the stamen and pistil in S. rostratum. 

 In C. marilandica, the pollen for fertilization, as well as for the 

 attraction of the insect visitor, is furnished by the small sta- 

 mens, while the pollen produced by the large stamens appears 

 to have no function. 11 The condition is not so specialized in the 

 species of Solarium under consideration. Here the pollen pro- 

 duced by the small anthers serves for the attraction of insects 

 and, as it seems to the writers, for fertilization, while the large 

 stamen, in connection with the pistil, serves as a support for 

 the visiting insect, and possibly furnishes some pollen for cross- 

 fertilization. 12 



In reference to the relative amount of pollen produced by a 

 large and small stamen, Halstead has given a note, in his paper 

 in the Botanical Gazette." The material in the hands of the 

 writers at the time of the writing of this paper is not suitable 

 for a verification of Mr. Halstead's results ; consequently they 

 are simply quoted on his authority. Even if the amount of 

 pollen produced by the large anther is no greater than that pro- 

 duced by one of the smaller, it is still very considerable, as may 

 be readily seen by tapping it out on a glass slip. He says : 



"The single large stamen of Solatium rostratum, with its beak- 

 like appearance, is a giant among its fellows, but does not ex- 

 ceed them in the production of pollen, for, while three or four 

 times larger than the others, its theeae are reduced to narrow, 

 curved lines of mother-cells. The ordinary stamens, on the 

 the other hand, possess unusually large cavities in which the 

 pollen is borne. The giant stamen, in cross-section, is shown 

 at a, in fig. 3, while a similar section of an ordinary stamen is 

 shown at b. The almost infertile condition of the large stamen 

 reminds one of the structure of the stamens of the cultivated 



11. This, of course, in case, as Meehan states, the large anthers do not dehisce. Of course 

 t be statement loses entirely its significance if, as Robertson states, the large stamens furnish 

 pollen for cross-fertilization. 



12. While the experiments made upon artificial pollination were very limited, it will be 

 seen that the pollen from the large stamen in no case fertilized over twenty-nine per cent, of the 

 (lowers pollinated from it. These flowers, however, were on the same raceme; so the low per 

 cent, might be due to this, or to the mechanical manipulation. The suggestion that the pollen 

 of the large stamen is less fertile than that of the smaller ones is at least interesting as a work- 

 ing hypothesis. 



13. Notes on Stamens of Solanacese , Bot. Gaz., vol. XV, pp. 103-106, 1890. 



