The natural history of plants, their forms, growth, reproduction, and distribution; . ch has meanwhile becomethicker, and these traverse the walls like cords, repeatedly branching and intersect-ing, and form actual net-works, often becoming several metres long. These latterroots do not help much in fastening the stem to the supporting wall; they areabsorbent roots, and take up the atmospheric water, with its abundance of foodmaterials, which has condensed or trickled down the bark of trees and rock walls. The clasping roots borne by the stems of Wightia, a genus of Scrophulariaceaegrowing in t
The natural history of plants, their forms, growth, reproduction, and distribution; . ch has meanwhile becomethicker, and these traverse the walls like cords, repeatedly branching and intersect-ing, and form actual net-works, often becoming several metres long. These latterroots do not help much in fastening the stem to the supporting wall; they areabsorbent roots, and take up the atmospheric water, with its abundance of foodmaterials, which has condensed or trickled down the bark of trees and rock walls. The clasping roots borne by the stems of Wightia, a genus of Scrophulariaceaegrowing in the mountainous regions of the Himalayas, and of several species offig in the same district, may be regarded as a fourth type. The attachment of theyoung shoots is brought about here as in the form just described by the finely-branched but not much elongated roots, which soon dry up. But when the climbingstem begins to thicken much stronger roots arise which surround the supportingtree-trunk like clamps and actually engirdle it. These girdle-like clasping roots CLIMBING PLANTS. 703. Fig. 167.—Ivy (Hedeia lielix) fdsteued by tlimbing roots to the truuk of au Oak giouiug lu the woods uear UoiJelU-Tt;. 704 CLIMBING PLANTS. often fuse at the places where they adjoin one another and increase in circumfer-ence, frequently becoming as thick as a mans arm. The illustration on the nextpage (fig. 168), taken from a photograph at Darjeeling in the Himalayas, showsthese stems, which look as if they had been actually tied on to the smooth trunksof tall trees, and which bend away somewhat from the support, and then ramifyand develop abundant leafy branches. Many tropical species of fig, which may serve as representatives of a fifth type,exhibit the following peculiarities: — their climbing roots, nestling to the sub-stratum, flatten and spread out like a doughy plastic mass; the adjacent rootsfuse together, and in this way irregular lattice-works, or incrusting mantles, onlyinterrupted he
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1902
