File:The natural history of plants, their forms, growth, reproduction, and distribution; (1902) (14596959497).jpg

Identifier: naturalhistoryof01kern (find matches)
Title: The natural history of plants, their forms, growth, reproduction, and distribution;
Year: 1902 (1900s)
Authors: Kerner von Marilaun, Anton, 1831-1898 Oliver, Francis Wall, 1864- Macdonald, Mary Frances Ewart Busk, Marian Balfour, Lady
Subjects: Botany
Publisher: London, Blackie
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

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tance of the conducting tubes, must be minimized as much aspossible. The forward movement of fluids in a channel is, however, renderedmore diflacult as the tube narrows, because in a narrower tube a relatively largeramount of the fluid adheres to the inner surface, and therefore it is necessary, inorder to obtain a rapid movement, that this adhesion be reduced as far as possible.This is most simply effected by widening the channel, since the adherent surfaceis thus diminished in comparison with the large amount of the fluid passingthrough. As a matter of fact, in the stems of climbing palms relatively very widetubes are to be seen, through which a large quantity of fluid can be broughtfrom the roots to the transpiring leaf-surfaces in a very short time, and thisactually occurs. The climbing palm, Calamus angustifolius, has eonductmg tubes THE VASCULAR TISSUES AND TRANSPIRATION. 363 of more than ; mm. diameter, and in the species of Rotang illustrated in fig. 94they are almost as wide.
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iig. 94.—Indian Climbing Palms (Rotang). From a photograph. What has been stated here with especial regard to the Rotang or Climbing Palmapplies also to all other twining and climbing plants known by the name of lianes,and their sap-conducting tubes are the wider, the longer their stems and the larger 364 THE VASCULAR TISSUES AND TRANSPIRATION. their transpiring leaves. In very many lianes the cavities of the conducting vessels!can be plainly seen with the naked eye. This is the case, for example, in the cross-1section of the liane represented in natural size in fig. 95 ^. A diameter of J mm. is

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