previous slight inclination; and the ordinary revolving movement
would then go on as before. I have described this curious case with
some care, because it first led me to understand the order in which,
as I then thought, the surfaces contracted; but in which, as we now
know from Sachs and II. de Vries, they grow for a time rapidly, thus
causing the shoot to bow towards the opposite side.

The view just given further explains, as I believe, a fact observed
by Mohl (p. 135), namely, that a revolving shoot, though it will
twine round an object as thin as a thread, cannot do so round a thick
support. I placed some long revolving shoots of a Wistaria close to
a post between 5 and 6 inches in diameter, but, though aided by me in
many ways, they could not wind round it. This apparently was due to
the flexure of the shoot, whilst winding round an object so gently
curved as this post, not being sufficient to hold the shoot to its
place when the growing surface crept round to the opposite surface of
the shoot; so that it was withdrawn at each revolution from its
support.

When a free shoot has grown far beyond its support, it sinks
downwards from its weight, as already explained in the case of the
Hop, with the revolving extremity turned upwards. If the support be
not lofty, the shoot falls to the ground, and resting there, the
extremity rises up. Sometimes several shoots, when flexible, twine
together into a cable, and thus support one another. Single thin
depending shoots, such as those of the Sollya Drummondii, will turn
abruptly backwards and wind up on themselves. The greater number of
the depending shoots, however, of one twining plant, the Hibbertia
dentata, showed but little tendency to turn upwards. In other cases,
as with the Cryptostegia grandiflora, several internodes which were