[293]

Oct. 30th 1877

Fern Nephrodium molle

nearest approach to Cotyledon.

Nutation important for Lygodium & being Heliotropic

(Kept in dark)

Selected a fern bearing single minute leaf .16 of inch long & .2 broad supported on petiole or rachis like a hair .23 long. The distal end of leaf divided slightly into 3 lobes & older fern in same pot bore 3 leaflets (perhaps get name). I fixed very thin glass filament with white point to leaf which projected .36 of inch beyond leaf & exaggerated angular movement & fixed mark below so that the tracing on Horizontal glass plate exaggerated the movement see Diagram of white point 47.6 times

First dot made at 9° a.m. & last at 9° 5' P.m. During this time the point changed its course 18 times, forming complex zig-zags, then returning almost parallel within 1/2 hour of its former course. There can be no doubt about nutation — greatest movements after 4° P.m. to 6° P.m.

[Movement in plants, p. 66: "Nephrodium molle (Filices).—A seedling fern of this species came up by chance in a flowerpot 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 .36 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 complex 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 circumnutation 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."]