A manual of botany / by J. Reynolds Green.

  • Green, J. Reynolds (Joseph Reynolds), 1848-1914.
Date:
1897-1902
Catalogue details

Licence: In copyright

Credit: A manual of botany / by J. Reynolds Green. Source: Wellcome Collection.

    31/540 (page 11)
    artificial system have, therefore, no necessary agreement with each other except in the characters selected for convenience as the types of those divisions respectively. Hence such a system may be compared to a dictionary, in which words are arranged, for convenience of reference, in an alphabetical order, adjacent words having no necessary agreement with each other, except in commencing with the same letter. In the Natural System, on the contrary, all the characters of the genera are taken into consideration, and those are grouped together into orders which correspond in the greatest number of important characters ; and the orders are again united, upon the same principles, into groups of a higher order, namely, the classes and other divi- sions. It must be evident, therefore, that all the knowledge we necessarily gain by an artificial system is the name of an unknown plant, while on the other hand, by the natural system, we learn not only the name, but also its relations to the plants by which it is surrounded, and hence get a clue to its structure, properties, and history. Thus, supposing we find a plant, and wish to ascertain its name, if we turn to the Lin mean System and find that such a plant is the Menyanthes trifoliata, this name is the whole amount of the knowledge we have gained; but by turning to the Natural System instead, and finding that our plant belongs to the order Gentianacecs, we ascertain at once from its affinities that it probably has the tonic and other properties which are possessed by the plants generally of that order, and, at the same time, we also learn that it accords in its structure with the same plants. It is quite true that all the orders, as at present constituted, are by no means so natural as that of the Gentianacese, but this arises from the present inperfection of our systems, and can only be remedied as our knowledge of plants extends ; a system, devised as perfectly as possible one day, may be deficient the next, in consequence of the discovery of new plants which may compel us to alter our views, for at present we are only imperfectly acquainted with the floras of many regions of the globe, and those of others are almost entirely unknown. Sufficient, however, is now known of plants to enable us to establish certain great divisions according to a natural method, which subsequent discoveries are not likely to affect to any important extent. The present imperfections (if the Natural System are, therefore, comparatively unimportant, and will no doubt disappear as our knowledge of the flora of the globe becomes extended. Having now described the general characters upon which