M., descending again late in the night or in the
very early morning.
* A. Brongniart first observed that the leaves of this plant and of
Marsilea sleep: see 'Bull. de la Soc. Bot. de France,' tom. vii. 1860, p.
470.
[page 392]
On the second day the descending line zigzagged slightly. As usual, the
ascending and descending lines did not coincide. On another occasion, when
the temperature was a little higher, viz., 24o - 26 1/2o C., a leaf was
observed 17 times between 8.50 A.M. and 12.16 P.M.; it changed its course
by as much as a rectangle six times in this interval of 3 h. 26 m., and
described two irregular triangles and a half. The leaf, therefore, on this
occasion circumnutated rapidly and in a complex manner.
Fig. 165. Strephium floribundum: circumnutation and nyctitropic movement of
a leaf, traced from 9 A.M. June 26th to 8.45 A.M. 27th; filament fixed
along the midrib. Apex of leaf 8 1/4 inches from the vertical glass; plant
illuminated from above. Temp. 23 1/2o - 24 1/2o C.
ACOTYLEDONS.
Marsilea quadrifoliata (Marsileaceae).--The shape of a leaf, expanded
horizontally during the day, is shown at A (Fig.
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