G YRA TION OF PLANTS. 1 63 



course completely seven times in eleven hours, but 

 moved to only a very small distance. On both days 

 the leaf rotated in the forenoon, fell in the afternoon, 

 and then rose, falling again during the night or early 

 morning. 



Peculiar movement in the frond of a fern has been 

 recorded by Professor Asa Gray. "A tuft of 

 Asplenimn tricJionianes, gathered last autumn in the 

 mountains of Virginia, is growing in the house of 

 Mr, Loomis, in a glass dish. About two months 

 ago he noticed that one of the fronds, — a rather 

 short and erect one, which is now showing fructifica- 

 tion, — made quick movements alternately back and 

 forth, at right angles to the frond, through from 20° 

 to 40°, whenever the vessel was brought from its 

 shaded situation into sunlight or bright daylight. 

 The movement was more extensive and rapid \\\\q.\\ 

 the frond was younger. When I first saw it (on 

 23rd January), its compass was within 15°, and was 

 about as rapid as that of the leaflets of Desmodhun 

 gyrans. It was more rapid than the second hand of 

 a watch, but with occasional stops in the course of 

 each half-vibration. This was in full daylight, next 

 a window, but not in sunshine. No movement 

 had been obser\'ed in the other fronds, which were all 

 sterile and reclining, with the exception of a single 

 one which was just unfolding, in which Mr. Loomis 

 thinks he has detected incipient motion of some 



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