Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 29, 2025
Their curvature usually increased greatly in from 15 m. to 20 m., and they became straight again in between 5 hrs. and 6 hrs., but on one occasion in 3 hrs. When a petiole has fairly clasped a stick, it is not able, on the removal of the stick, to straighten itself. The free upper part of one, the base of which had already clasped a stick, still retained the power of movement.
How the boys sailing about in their boats when the day chances to be very hot, are in the habit of plucking one of its large shining leaves out of the water, and spreading it over their crowns, to protect them from the fervid rays of the sun; and how the petiole of the leaf, being hollow inside, serves them as a tube for drinking out of.
FUMARIACEAE. Fumaria officinalis. It could not have been anticipated that so lowly a plant as this Fumaria should have been a climber. It climbs by the aid of the main and lateral petioles of its compound leaves; and even the much-flattened terminal portion of the petiole can seize a support. I have seen a substance as soft as a withered blade of grass caught.
A loop of thread, weighing one-eighth of a grain, caused, after 12 hrs. and before 20 hrs, had elapsed, a considerable curvature; but it was never fairly clasped by the petiole. The young internodes are in continual movement, which is considerable in extent, but very irregular; a zigzag line, or a spire crossing itself; or a figure of 8 being formed.
That also was almost ready for use, and my uncle said we should have a good supply for the voyage. The leaves, as soon as they have grown to a sufficient size, are plucked off, and the petiole and part of the midrib are cut away. The leaves are then cut transversely into strips about one-sixteenth of an inch wide.
The two opposite petioles do not move together, and one is sometimes so much raised as to stand close to the stem, whilst the other is not far from horizontal. The basal part of the petiole moves less than the distal part. The tendrils, besides being carried by the moving petioles and internodes, themselves move spontaneously; and the opposite tendrils occasionally move in opposite directions.
As the sensitiveness is here greater than in any other species of the genus observed by me, and is in itself remarkable, I will give fuller details. Full-grown petioles are not in the least sensitive. A thin stick placed so as to press lightly against a petiole, having a leaflet a quarter of an inch in length, caused the petiole to bend in 3 hrs. 15 m.
In Mutisia clematis, the tendril, in shape and colour, closely resembles the petiole of one of the ordinary leaves, together with the midribs of the leaflets, but vestiges of the laminae are still occasionally retained. In four genera of the Fumariaceae we can follow the whole process of transformation.
A young petiole, when rubbed, became slightly curved in 17 m.; and afterwards much more so. It was nearly straight again in 8 hrs. Tropaeolum tuberosum. On a plant nine inches in height, the internodes did not move at all; but on an older plant they moved irregularly and made small imperfect ovals. These movements could be detected only by being traced on a bell-glass placed over the plant.
The power of twining is like that of the last species. Its leaves are nearly similar in structure and in function, excepting that the sub-petioles of the lateral and terminal leaflets are sensitive. A loop of thread, weighing one-eighth of a grain, acted on the main petiole, but not until two or three days had elapsed.
Word Of The Day
Others Looking