Copy 1

Descriptive and physiological botany / by J.S. Henslow.

  • John Stevens Henslow
Date:
1836
Catalogue details

Licence: Public Domain Mark

Credit: Descriptive and physiological botany / by J.S. Henslow. Source: Wellcome Collection.

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    gans of which a plant is composed are familiar to every one. They are, the root, stem, branches, leaves, flowers, &c. These organs may be conveniently grouped under two heads, characterised by the nature of the functions which they are severally destined to perform. The root, stem, branches, leaves, and some other appendages to each of these, are concerned in carrying on the func- tion of nutrition, or that act by which the life of every separate individual is maintained; and these are, in consequence, styled the ‘ Conservative” organs. The flower and fruit, with their various appendages, are connected with the function of reproduction, by which the continuance of the species is provided for; and these are, therefore, named the “ Reproductive” organs. (10.) Conservative Organs. — The conservative or- gans, again, may be separated into two series. Every one is acquainted with the fact, that the stems of most plants are above ground, and that they affect a more or less erect position, and are constantly being developed upwards, whilst the roots of most plants penetrate the soil with an evident tendency downwards. An imagin- ary plane, intersecting the plant at the point whence these opposite tendencies originate, is called the neck : the stem, and the various organs which accompany it, are styled the “ ascending,” and the root and its ap- pendages the “ descending” series. But these defin- itions do not exactly represent the truth, since there are certain stems which are strictly subterranean, and have a tendency to creep below the surface of the soil; whilst there are also certain roots which are aérial, and some of these scarcely indicate any downward tendency. The terms employed in defining the two series must, there- fore, be considered as indicating certain facts, which are very generally, though not universally; applicable to the several organs included under each. (11.) Reproductive Organs.— The reproductive or- gans may also be classed under two series. ‘The first is the ‘‘ Inflorescence,” which includes the flower and the various appendages to that part of the stem on
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