CLASSIFICATION OF PLANTS. 203 
The twenty-four classes being thus fixed, Linnzus, after some 
consideration, subdivided each of them—the thirteen first classes 
according to the number of their styles or distinct stigmata; the 
fourteenth (Didynamia) by the disposition of their seeds, some- 
times bare (or at least what he considered as such), sometimes 
enclosed in a pericarp; the fifteenth (Tetradynamia) according 
to the form of the fruit; the sixteenth, seventeenth, eighteenth, 
and twentieth according to the absolute number of their stamens ; 
the two following from the absolute number of their stamens, and 
from the manner of their adherence; the twenty-third class 
(Polygamia), from the distribution of the hermaphrodite and 
unisexual flowers upon the same plant, or upon two or three 
different. The nineteenth class (Syngenesia) is divided as follows :— 
I. Flowers all fertile, hermaphroditic (Polygamia equalis), Goats- 
beard, Lettuce, Thistle. 
II. Hermaphrodital flowers, fruitful in the disks ; female flowers, 
fruitful at the circumference (Polygamia superflua), Tansy, Worm- 
wood, Groundsel. 
III. Hermaphrodital flowers, fruitful in the disk; neutral flowers, 
sterile at the circumference (Polygamia frustranea), Centaury, Sun- 
flower. 
IV. Hermaphrodital flowers, sterile in their disks; female flowers, 
fertile at the circumference (Polygamia necessarea), Marigold. 
V. Flowers provided with a proper and clustered calyx, under a 
common calyx (Polygumia segregata); separated flowers (Mono- 
gamia), Lobelia, Violet: 
This classification of plants has received the name of the artificial 
system, because it groups the species according to a small number, 
and not from the whole of their characteristics ; in short, it rather 
permits one species to be distinguished from another, than makes 
each known in an intimate manner. It insists much upon their 
differences, little upon their resemblances. Between species thus 
compared, only one essential analogy may exist. The Rush takes 
place beside the Barberry, because each of these plants have six 
stamens and only one style. The Vine is ranged beside the Peri- 
winkle, because they each have five stamens and one style. The 
Carrot is allied to the Gooseberry, &c. There may not be between the 
plants thus compared any natural bond, any essential characteristic, 
