We now come to a small section of plants which climb by means of the
produced midribs or tips of their leaves.

LILIACEAE.--Gloriosa Plantii.--The stem of a half-grown plant
continually moved, generally describing an irregular spire, but
sometimes oval figures with the longer axes directed in different
lines. It either followed the sun, or moved in an opposite course,
and sometimes stood still before reversing its direction. One oval
was completed in 3 hrs. 40 m.; of two horseshoe-shaped figures, one
was completed in 4 hrs. 35 m. and the other in 3 hrs. The shoots, in
their movements, reached points between four and five inches asunder.
The young leaves, when first developed, stand up nearly vertically;
but by the growth of the axis, and by the spontaneous bending down of
the terminal half of the leaf, they soon become much inclined, and
ultimately horizontal. The end of the leaf forms a narrow, ribbon-
like, thickened projection, which at first is nearly straight, but by
the time the leaf gets into an inclined position, the end bends
downwards into a well-formed hook. This hook is now strong and rigid
enough to catch any object, and, when caught, to anchor the plant and
stop the revolving movement. Its inner surface is sensitive, but not
in nearly so high a degree as that of the many before-described
petioles; for a loop of string, weighing 1.64 grain, produced no
effect. When the hook has caught a thin twig or even a rigid fibre,
the point may be perceived in from 1 hr. to 3 hrs. to have curled a
little inwards; and, under favourable circumstances, it curls round
and permanently seizes an object in from 8 hrs. to 10 hrs. The hook
when first formed, before the leaf has bent downwards, is but little
sensitive. If it catches hold of nothing, it remains open and
sensitive for a long time; ultimately the extremity spontaneously and
slowly curls inwards, and makes a button-like, flat, spiral coil at