30 KANSAS UNIVERSITY SCIENCE BULLETIN. 



ceive pollen, and fertilization to be effected, especially if the 

 pollen from the small stamens is functional. 



Among other insects found visiting the plant, the honey-bee 

 was most frequent. 



As will be noticed from our list, some insects visit the plants 

 without effecting cross-pollination. Those insects which obtain 

 pollen in an illegitimate manner do not secure it from the small 

 stamens exclusively, but almost invariably visit the large sta- 

 men as well. 



The adaptation of the plant to propagation by the production 

 of seeds is of considerable significance. 14 



A normal plant will produce in the neighborhood of 7000 

 seeds. In making observations on this point, it was found from 

 five pods examined there was an average of fifty-six seeds. 



Pod 1 contained 66 seeds. 



(I C) it -•> (I 



" 3 " 51 " 



" 4 " 53 " 



" 5 " 58 



281 seeds; av., 56. 



Pods 4 and 5 were from the same plant but separate racemes ; 

 the others were from different plants. In determining the 

 average number of seeds produced by the plant, five plants 

 growing normally and in different localities were observed, with 

 the following results : 



Plant 1 192 pods. 



" 2 50 " 



" 3 66 " 



" 4 113 " 



" 5 210 " 



Taking the average of fifty-six seeds per pod obtained above, 

 we see that the plant producing 122.5 pods, the average from 

 the preceding table, would produce about 7000 seeds. 



One plant was observed upon which occurred fifty-five to 

 sixty racemes. Allowing the low average of six pods to the 

 raceme, the plant will produce in the neighborhood of 20,000 

 seeds. Occasionally a very large plant is observed which pro- 



14. Observations on the number of seeds produced and the surety of fertilization may be of 

 especial interest, when the wonderful distribution which this plant has attained in recent years 

 is taken into consideration. The original habitat of S. rostralum was the southwestern por- 

 tion of the United States. It has since spread over a large part of the United States, in many 

 places being recognized as a very noxious weed. It is also reported from several European lo- 

 calities. Reports on the destructiveness of the plant as a weed may be found in publications of 

 the agricultural departments, as: Dewey, L. H., A Weed Bulletin, Farmers' Series, No. 28, U. 

 S. Dept. Agr. ; Pammel, L. H., Two Noxious Weeds, Bull. Iowa Exp. Sta., 1895. L. H. Pammel, 

 — Distribution of Some Weeds in the United States, especially Iva xaiithifolia, Lacluca 

 scariola, Solatium carolinewm, and Molanum rostratum, Proc. Iowa Acad. Sci., 1895, vol. II, 

 pp. 103-127 — gives the eastward migration of this weed up to 1895. 



