. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. SENSITIVENESS O/.' LEAVES. 419 1083. In some cases tendrils are not sensitive to contact, but are distinctly apheliotropic, turning- away from tlie light, and in tliis wa3' securing for the plant an adequate mechanical support upon some wall or the like. Grape-vines and Virginia creeper furnish good examples of such tendrils. The branches of the tendrils of the grape-vine sometimes clasp around a slender sup- port, somewhat in the same way as an object would be
. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. SENSITIVENESS O/.' LEAVES. 419 1083. In some cases tendrils are not sensitive to contact, but are distinctly apheliotropic, turning- away from tlie light, and in tliis wa3' securing for the plant an adequate mechanical support upon some wall or the like. Grape-vines and Virginia creeper furnish good examples of such tendrils. The branches of the tendrils of the grape-vine sometimes clasp around a slender sup- port, somewhat in the same way as an object would be grasped by a thumb and finger. The much-branched tendrils of species of Ampelopsis are also apheliotropic; but when the tips of the branches of the tendrils come in contact with a wall, they become expanded into flat discs which cling to the surface. 1084. Sensitiveness of petioles. This can be easily examined in the common climbing species of Clematis,in Solanura jasminoides, etc. The leaves circumnutate and, in the case of compound leaves, the separate leaflets also. When 3'oung the sides of the petioles are sensitive to touch, bending towards where the pres- sure or compact is. Shortly after clasping the support by means of this bending the petioles increase in thickness, become stronger and tougher than before, and sometimes take on a structure suggestive of a rigid branch. In Gloriosa the sensitiveness is very marked in the leaf-tips, but only on the under surface of the pro- longed thread-like extremity. 1085. Sensitiveness of leaf-blades. The fly-trap of Dionsea (considered by some an appendage to the proper leaf-blade) is exquisitely sensitive to any touch upon the hairs which grow on the faces of the trap. As soon as these are touched the trap instantly closes, and the same effect follows a slight touch on the median line. A cross-section through the leaf shows that the parenchyma is thin-walled. The leaf of the small water- plant Aldrovanda has likewise been shown t
Size: 1158px × 2159px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectplantanatomy, bookyea
