ifferent plants that I felt much
inclined to consider spontaneous revolving movement or circumnutation as
common to all plants and the movements of climbing plants as a
special modification of that general phenomenon. And this you have now
convincingly, nay, superabundantly, proved to be the case.

I was much struck with the fact that with you Maranta did not sleep for
two nights after having its leaves violently shaken by wind, for here we
have very cold nights only after storms from the west or south-west,
and it would be very strange if the leaves of our numerous species of
Marantaceae should be prevented by these storms to assume their usual
nocturnal position, just when nocturnal radiation was most to be feared.
It is rather strange, also, that Phaseolus vulgaris should not sleep
during the early part of the summer, when the leaves are most likely to
be injured during cold nights. On the contrary, it would not do any harm
to many sub-tropical plants, that their leaves must be well illuminated
during the day in order that they may assume at night a vertical
position; for, in our climate at least, cold nights are always preceded
by sunny days.

Of nearly allied plants sleeping very differently I can give you
some more instances. In the genus Olyra (at least, in the one species
observed by me) the leaves bend down vertically at night; now,
in Endlicher's "Genera plantarum" this genus immediately precedes
Strephium, the leaves of which you saw rising vertically.

In one of two species of Phyllanthus, growing as weeds near my house,
the leaves of the erect branches bend upwards at night, while in the
second species, with horizontal branches, they sleep like those of
Phyllanthus Niruri or of Cassia. In this second species the tips of
the branches also are curled downwards at night, by which movement
the youngest leaves are yet better protected. From their vertical
nyctitropic position the leaves of this Phyllanthus might return to
horizontality, traversing 90 deg, in two ways, either to their own or to
the opposite side of the branch; on the latter way no rotation would be
required, while on the former each leaf must rotate on its own axis in
order that its upper surface may be turned upwards. Thus the way to the
wrong side appears to be even less troublesome. And indeed, in some rare
cases I have seen three, four or even almost all the leaves of one side
of a branch horizontally expanded on the opposite side, with the