36 THE AMERICAN BOTANIST 



where she lays her egg^s within the pistil by means of her 

 ovipositor. Here a wonder occurs. It is only when the 

 flowers are young, generally not over two days old, that the 

 pistils are susceptible of pollination. The moth seems to know 

 this and never oviposits in older flowers. As soon as she de- 

 posits her eggs she goes to the top of the pistil and pushes 

 her load of pollen as far into the tube as she can. In a few 

 days the egg hatches and the larvae feed on the young and 

 tender sedd's. Enough seeds, however, are left to perpetu- 

 ate the species. 



The consideration of this plant and moth with their in- 

 terdependence forms an interesting study. To see the moth 

 at work one will have to do his observing after nightfall and 

 with an artificial light of some kind. When one has observed a 

 few things for himself then let him seek some good authority 

 who has made a life study of yucca and Pronuba. I would 

 refer those who wish to know more on the subject to the Third 

 Annual Report of the Missouri Botanical Garden where they 

 will find a long article by that profound insect authority, C. 

 V. Riley, to which I am indebted for much information. 



Ft. Liipton, Colo. 



BY THE RIVER'S BRIM. 



By Frank Dobbin. 



A WALK by the river side is always interesting as one is 

 sure to make some interesting finds. If the stream 

 be sluggish with plenty of mud on the bottom some of the 

 numerous Potamogetons will be found or the long streamers 

 of the eel grass ( Vallisneria spiralis) will point the direction 

 of the slow moving current. The submerged rocks and 

 stones may be dark with the long stems of some moss of the 

 genus Fontinalis — possibly F. dalecarlica or F. N ovae-An- 

 gliae, or if it be a favorable locality the curious seaweed-like 

 plant, the river weed {Podestemon ceratophyllum) may be 



