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The young internodes, likewise revolved irregularly in ellipses or spires; so that by these combined movements a considerable space was swept for a support. If the terminal and attenuated portion of a petiole fails to seize any object, it ultimately bends downwards and inwards, and soon loses all irritability and power of movement.
The extremity of the petiole, from which the young tendril arose, was two inches from the glass, so that if a pencil two inches in length could have been affixed to the petiole, it would have traced the annexed figure on the under side of the glass; but it must be remembered that the figure is reduced by one-half.
In another case a petiole curled completely round a stick in 12 hrs. These petioles were left curled for 24 hrs., and the sticks were then removed; but they never straightened themselves.
The petiole of the leaf and the lower parts of the tendril, halfway between the upper leaflet and the lowest branch, are not sensitive. A tendril after curling from a touch became straight again in about 6 hrs., and was ready to re-act; but one that had been so roughly rubbed as to have coiled into a helix did not become perfectly straight until after 13 hrs.
I was enabled to observe the spontaneous movements of the petioles better in this than in the two preceding species: one petiole described three small vertical ellipses in the course of 11 hrs., whilst another moved in an irregular spire.
The exterior surface generally becomes bright red. But a far greater change takes place in the nature of the tissues than that which is visible: the petiole of the unclasped leaf is flexible and can be snapped easily, whereas the clasped one acquires an extraordinary degree of toughness and rigidity, so that considerable force is required to pull it into pieces.
Neglecting the first great sweep towards the light from the figure 1 to 2, the end of the petiole swept a space 4 inches across in one direction, and 3 inches in another. As a full-grown tendril is considerably above two inches in length, and as the tendril itself bends and revolves in harmony with the internode, a considerably wider space is swept than is here represented on a reduced scale.
I may here state that I ascertained in all cases the weights of the string and thread used by carefully weighing 50 inches in a chemical balance, and then cutting off measured lengths. The main petiole carries three leaflets; but their short, sub-petioles are not sensitive.
In this species, and in no other leaf-climber seen by me, a full- grown leaf is capable of clasping a stick; but in the greenhouse the movement was so extraordinarily slow that the act required several weeks; on each succeeding week it was clear that the petiole had become more and more curved, until at last it firmly clasped the stick.
There is a tree common to the Columbia river below the entrance of cataract river which in it's appearance when divested of it's foliage, much resembles the white ash; the appearance of the wood and bark is also that of the ash. it's stem is simple branching and diffuse. the leaf is petiolate, plane, scattered, palmate lobate, divided by four deep sinuses; the lobes are repand, or terminate in from 3 to 5 accute angular points, while their margins are indented with irregular and somewhat circular incissures. the petiole is celendric smooth and 7 inches long. the leaf 8 inches in length and 12 in bredth. this tree is frequently 3 feet in diameter and rises to 40 or 50 feet high. the fruit is a winged seed somewhate like the maple. in the same part of the country there is also another growth which resembles the white maple in it's appearance, only that it is by no means so large; seldom being more than from 6 to 9 inches in diamater, and from 15 to 20 feet high; they frequently grow in clusters as if from the same bed of roots spreading and leaning outwards. the twigs are long and slender. the stems simple branching. the bark smooth and in colour resembling that of the white maple. the leaf is petiolate, plane, scattered nearly circular, with it's margin cut with accute angular incissures of an inch in length and from six to 8 in number the accute angular points formed by which incissures are crenate, or cut with small accute angular incissures. or in this form. it is 3 inches in length, and 4 in width. the petiole celindric smooth and one and a 1/4 inches long. the fruit or flower not known.
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