258 CIECUTHNUTATION OF CEYPTOGAMS. Chap. 17 



Fig. 120. 



In the chapter on the Sleep of Plants the conspicuous circum- 

 nutation of Marsilea guadrijdliata (Marsileacese, Pam. 4) will be 

 described. 



It has also been shown in Chap. I. that a very young SeZo- 

 gindla (LycopodiacesB, Fam. 6), only '4 inch in height, plainly 

 eircumnutated ; we may therefore conclude that older plants^ 

 whilst growing, would do the same. 

 (35.) Lunularia vulgaris (Hepaticae, Fam. 11, Muscales). — 

 The earth in an old flower-pot was 

 coated with this plant, bearing 

 gemmae. A highly inclined frond, 

 which projected '3 inch above the 

 soil and was '4 inch in breadth, was 

 selected for observation. A glass 

 hair of extreme tenuity, '75 inch 

 in length, with its end whitened, 

 was cemented with shellac to the 

 frond at right angles to its breadth ; 

 and a white stick with a minute 

 black spot was driven into the soil 

 close behind the end of the hair. 

 The white end could be accurately 

 brought into a line with the black 

 spot, and dots could thus be suc- 

 cessively made on the vertical 

 glass-plate in front. Any move- 

 ment of the frond would of course 

 be exhibited and increased by the 

 long glass hair; and the black spot 

 was placed so close behind the end 

 of the hair, relatively to the dis- 

 tance of the glass-plate in front, 

 that the movement of the end was 

 magnified about 40 times. Never- 

 theless, we are convinced that onr 

 tracing gives a fairly faithful re- 

 presentation of the movements of 

 the frond. In the intervals between each observation, the plant 

 was covered by a small bell-glass. The frond, as already stated, 



Cnnnlnria vulgiris: oircumnuta- 

 tion of a ifrond, traced from 

 9 A.M. Oct 25th to 8 A.M. 27th. 



rircnmnutation as it ooours only 

 when the plant is exposed to the 

 light ; even artifioial light " is 



sufficient to excite motion 

 few minutes." 



for a 



