179 



made by Amos Eaton in his botany published in 1824, that the 

 leaflets of Onoclea " slowly approach each other on squeezing the 

 stem with the hand," * prompted me to determine, if possible, 

 what basis of fact there might lie beneath it. 



Accordingly an attempt was made, in rather crude fashion, to 

 be sure, to determine whether there was any movement rapid 

 enough for ready observation. I was encouraged to do this by 

 the experience which I had in noticing that the lowermost leaflets 

 did approach each other sensibly within a period of ten minutes 

 after plucking. 



A series of experiments was carried out by cutting off the 

 petioles of the leaves desired close to the ground, and pouring'on 

 water to prevent the entrance of air into the tissues in the event 

 of negative pressure. Some were then measured by taking the 

 distance between the tips of the bottom pair of leaflets, and 

 between the tip of one of these and the apex of the leaf. The 

 latter measurement proved of no value, since the twisting of the 

 whole leaf vitiated the results. After measurement a few were 

 allowed to stand in water, and others allowed to dry, and in the 

 latter the movement of the leaflets was usually to be noted in 

 five minutes although in some cases negative results only were 

 obtained. Those remaining in water, on the other hand, usually 

 remained fresh and showed no movement. The measurements 

 of a few cases of leaves allowed to remain out of the water are 

 given. 



Time 



9-55 



10 



10.02 



10.15 



io-55 



Distance be- 

 tween tips of 

 leaflets in 

 inches. 



2)4, 



3H 



2}i 



3 l A 



2 



3% 



3rt 





Time. 



10.40 



10.45 



10.50 



11.30 





Distance be- 

 tween tips of 

 leaflets in 

 inches. 



23/ 



3 l /$ 

 3X 



2# 



2%. 



3X 



2% 

 2% 



3 l A 







*My attention was drawn to this statement of Eaton's by a paragraph, written by 

 Miss B. L. Putnam in the Fern Bulletin, 7 : 15. Ja. 1899. 



