Vol. XVI. No. 1 1— Botanical Gazette— Nov., 1891. 



The sliug.fruit of Cryptotsenia Canadensis. 



E. J. HILL. 



While passing through the woods in the autumn of 1890 

 my attention was called to the rattling of seeds falling on the 

 dry leaves which thickly covered the ground. Stopping to 

 see from what plant they came it was found to be Cryptotse- 

 nia Canadensis. Not knowing that there was anything pe- 

 culiar in its structure, trials were made of several plants to 

 learn by what contrivance a single one could throw its fruit all 

 around it under the influence of a blow. By striking the 

 stems near the base the fruit was scattered in all directions, 

 some being thrown to a distance of five or six feet. The 

 space on which it fell was somewhat elliptical in shape, the 

 longer diameter being in the line of direction of the blow. 

 It seemed a little paradoxical that a body, unless rebounding 

 from a surface against which it had been thrown, should trav- 

 erse the path over which the impulse came, but the fact that 

 it did was not to be denied after repeated trials had shown it. 

 Here was a phenomenon to be studied and an explanation 

 found. It was evident that the behavior of the fruit was in 

 some way connected with the elasticity of the stem and 

 branches and its mode of attachment to them. This was 

 about all that was determined on the spot, for' the fruit broke 

 away from its support so suddenly that the eye could not 

 readily follow the motion. Almost simultaneous with 

 the blow the sound of impact on the dry leaves was 

 heard. Some plants were carefully gathered and placed in a 

 vasculum to be taken home for study. The experiments then 

 tried have been repeated the present season, and the conclu- 

 sions reached at the time confirmed by numerous trials. The 

 mechanism and operations by which the fruit is scattered are 



about as follows. ". 



The mericarps of Cryptotaenia when fully ripe split away 

 from each other and hang from the two parts of the carpo- 

 phore, which are separated above, like a versatile anther on 

 •ts filament. The branches of the carpophore are flat and 

 very slender. They curve over and are often bent a little 



