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We may suspect that, owing to the principle of correlation, the power of movement has been transferred to the flower-peduncles from the young internodes, and sensitiveness from the young petioles. Rhodochiton volubile. A long flexible shoot swept a large circle, following the sun, in 5 hrs. 30 m.; and, as the day became warmer, a second circle was completed in 4 hrs. 10 m.
The young internodes and tendrils of this anomalous member of the family, revolve in the same manner and at about the same rate as those of the Echinocystis. The stem does not twine, but can ascend an upright stick by the aid of its tendrils. The concave tip of the tendril is very sensitive; after it had become rapidly coiled into a ring owing to a single touch, it straightened itself in 50 m.
I rubbed some internodes one day on one side, and the next day either on the opposite side or at right angles to the first side; and the curvature was always towards the rubbed side. SOLANACEAE. Solanum jasminoides. Some of the species in this large genus are twiners; but the present species is a true leaf-climber.
If we consider leaf-climbers alone, the idea that they were primordially twiners is forcibly suggested. The internodes of all, without exception, revolve in exactly the same manner as twiners; some few can still twine well, and many others in an imperfect manner. Several leaf-climbing genera are closely allied to other genera which are simple twiners.
Plants which climb by the aid of spontaneously revolving and sensitive petioles Clematis Tropaeolum Maurandia, flower-peduncles moving spontaneously and sensitive to a touch Rhodochiton Lophospermum internodes sensitive Solanum, thickening of the clasped petioles Fumaria Adlumia Plants which climb by the aid of their produced midribs Gloriosa Flagellaria Nepenthes Summary on leaf-climbers.
Hence this plant appears to climb simply by its tendrils being brought, through the growth of the stem, or more efficiently by the wind, into contact with surrounding objects, which they then clasp. I may add that the tendrils, or the internodes, or both, of Vicia sativa revolve. COMPOSITAE. Mutisia clematis. The immense family of the Compositae is well known to include very few climbing plants.
The long, much-inclined shoot of the Ceropegia previously alluded to offered some curious peculiarities. The lower and older internodes, which continued to revolve, were incapable, on repeated trials, of twining round a thin stick; showing that, although the power of movement was retained, this was not sufficient to enable the plant to twine.
Although the power of twining has generally been lost, either from the stiffness or shortness of the internodes, from the size of the leaves, or from some other unknown cause, the revolving movement of the stem serves to bring the tendrils into contact with surrounding objects. The tendrils themselves also spontaneously revolve.
With the Hop we have seen that three internodes were at the same time revolving; and this was the case with most of the plants observed by me. With all, if in full health, two internodes revolved; so that by the time the lower one ceased to revolve, the one above was in full action, with a terminal internode just commencing to move.
The venation is very distinct. The outer leaves are smaller and, on examining the branch, it will be seen that their internodes do not make so large a growth as the leaves in the centre of the bud. Copper Beech. 1. Branch in winter state: a, leaf-scar; b, bud-scar. 2. The leaf-scars are small, soon becoming merely ridges running half round the stem.
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