The genera of South African plants : arranged according to the natural system / by William Henry Harvey.

  • William H. Harvey
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: The genera of South African plants : arranged according to the natural system / by William Henry Harvey. Source: Wellcome Collection.

    56/556
    types (as Leguminos<s, Compositge and other Monopetalos) stand towards the middle of the series, and the Orders of a lower type occupy the ends; thus the complete-flowered plants with much separated organs are those with which the series begins, and the incomplete-flowered Orders (some of which have no recognized affinity with higher ones) occupy the end of the series. The extent to which this system is artificial is best illus- trated by a few examples, thus:— 10, Bixaceee, passes into 58, Bassiflorecc, various genera ac- tually uniting the two. 16 and 17, Caryophyllea, passes into 62, Ficoidea, 99, Fliyto- lacceoR, 101, Amaranthacece, and 101, Faronychiecs. 22, Malvacece, passes into 109, Euphorhiacece. 31, Olacinea;, passes into 65, Cornea, 66, Lorantlincece, and 108, SantalacecB ; and many other cases might be quoted of Orders removed to three far distant groups by one or two characters alone, and these very inconstant ones. If it is asked, why then not bring all together ? The answer is, if we do,—1, we should lose all means of finding the locality of any genus, without hunting through every group ; and 2, we must often then intercalate betAveen two Orders that are most closely re- lated, another Order containing a vast number of ])lants not so much related to either Order as these two Orders ai’e to one another. For instance, if we bring Euphorhiacece in between Malvacece and Tiliacece, Ave break up the character of the class, subclass, group, series, and cohort under which Malvacece and Tiliacece are classed, and thrust betAveeu these a vast host of Euphorbiaceous genera that are not so nearly related to Mal- vacece as Tiliacece are. It must then be clearly understood, that the Natural Orders established throughout the vegetable kingdom are in the main perfectl}'^ natural groups, but that the so-called Natural sys- tem of plants is by no means a natural one, in respect of the sequence of the Dicotyledonous Orders, and that this is be- cause they cannot be arranged naturally in a linear series. To classify these Orders arbitrary characters have been sought and used, Avhich bring a larger proportion of them into proper position and sequence, but remove others very far from their proper places.—J. D. IIookee. CONSPECTUS OF THE CLASSES, COHOKTS, ETC. Class I. DICOTYLEDONES.—Stem, Avhen perennial,Avith pith concentric layers of Avood and bark. Leaves usually Avith branched and netted venation. Perianth usually of 4 or 5