66 



OIKCUMNUTATION OF SEEDLDIGS. 



Chap. I 



fig. 53. 



A filament was next fixed to a cotyledon only i of an inch in 

 heiglit, which was illuminated exclusively from above, and as 

 it was' kept in a warm greenhouse, it grew rapidly ; and now 

 there could be no doubt about its circumnutation, for it described 

 a figure of 8 as well as two small ellipses in 5i hours. 

 Nephrodium molle (Filices). — ^A seedling fern of this species 



came up by chance in a flower- 

 pot near its parent. The frond, 

 as yet only slightly lobed, was 

 only '16 of an inch in length and 

 •2 in breadth, and was supported 

 on a rachis as fine as a hair 

 and '23 of an inch in height. A 

 very thin glass filament, which 

 projected for a length of 'SB of 

 an inch, was fixed to the end of 

 the frond. The movement was 

 so highly magnified that the 

 figure (Fig. 53) cannot be fully 

 trusted; but the frond was 

 constantly moving in a compltx 

 manner, and the bead greatly 

 changed its course eighteen times in the 12 hours of observation. 

 Within half an hour it often returned in a line almost parallel 

 to its former course. The greatest amount of movement occurred 

 between 4 and 6 p.m. The circumnuta- 

 tion of this plant is interesting, because 

 the species in the genus Lygodium are 

 well known to circumnutate conspicuously 

 and to twine round any neighbouring 

 object. 



Selaginella Kraussii (?) (Lycopodiacefe). 

 —A very young plant, only '4 of an inch 

 in height, had sprung up in a pot in the 

 hot-house. An extremely fine glass fila- 

 ment was fixed to the end of the frond- 

 like stem, and the movement of the bead 

 traced on a horizontal glass. It changed its course several 

 times, as shown in Fig. 54, whilst observed during 13 h. 15 m., 

 and returned at night to a point not far distant from that 

 whence it had started in the morning. There can be no doubt 

 that this little plant circumnutated 



Nephrodium molle : circnmnutiticn 

 of very young frond, traced in 

 darkness on horizontal glass, 

 from 9 A M. to 9. P.M. Oct. 30th. 

 Movement of bead magnified 48 

 times. 



Fig. 54. 



Solaginella Kravssii (?) : 

 circumnutation of 

 young plant, kept in 

 darkness^ tr^iced fr^m 

 8.45 A.M. to 10 PM. 

 Oct. 31^t. 



