resupinatum two, and those of T. subterraneum three in this time. Again,
the leaflets of Oxalis Plumierii made a single ellipse; those of O.
bupleurifolia, two; those of O. Valdiviana, two or three; and those of O.
acetosella, at least five in the twenty-four hours.
The line followed by the apex of a leaf or leaflet, whilst describing one
or more ellipses during the day, is often zigzag, either throughout its
whole course or only during the morning or evening: Robinia offered an
instance of zigzagging confined to the morning, and a similar movement in
the evening is shown in the diagram (Fig. 126) given under Sida. The amount
of the zigzag movement depends largely on the plant being placed under
highly favourable conditions. But even under such favourable conditions, if
the dots which mark the position of the apex are made at considerable
intervals of time, and the dots are then joined, the course pursued will
still appear comparatively simple, although the number of the ellipses will
be increased; but if dots are made every two or three minutes and these are
joined, the result often is that all the lines are strongly zigzag, many
small loops, triangles, and other figures being also formed.
Pages:
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678