CLASSIFICATION OF PLANTS. XXl 
the names Monogynia, Digynia, Trigynia, ete., indicating respectively one, 
two, three, etc., styles. 
In the 14th class, or Didynamia, Linnxus took his ordinal characters 
from the structure of the fruit. When this is formed of four akenia, 
situated at the bottom of the calyx, so as to resemble naked seeds, he called 
the order Gymnospermia; and when the fruit was a capsule containing 
several seeds, he termed the group Angiospermia. Tetradynamia presents 
also two orders; the one with a silicule, the other with a siliqua; and 
hence they were called Siliculosz and Siliquose. A third order has been 
added by Sprengel, for such as have an indehiscent fruit; and De Candolle 
has proposed to subdivide the class according to the relative position of 
the cotyledons and radicle. The 16th, 17th, and 18th classes being accord- 
ing to the union of the filaments, the number of stamens is made to serve 
as a character for the orders. 
In Syngenesia, where the anthers are united, and there are almost always 
five stamens, other means were resorted to. Some florets were observed 
to be bisexual; others with stamens or pistils only. In reference, there- 
fore, to the 23rd class, Linneeus gave to each of the orders the name Poly- 
gamia, with another epithet to mark their respective peculiarities. The 
first he terms Polygamia equalis, all the florets being equally fertile and 
bisexual; the second, Polygamia superflua, where the florets of the dise 
are bisexual, but those of the circumference or ray female, both producing 
perfect seed; the third, Polygamia frustranea, have the florets of the dise 
bisexual and fertile, but those of the ray sterile and imperfect. In the 
second order the florets of the ray were only superfluous ; here they are 
totally useless. The fourth, or Polygamia necessaria, has the florets of 
the dise bisexual, but sterile from the imperfection of the stigmas ; those 
of the ray containing only pistils are fertilized by the pollen of the former. 
The fifth, Polygamia segregata, has all the florets bisexual, but each of 
them contained an involucre peculiar to itself; the whole, as in the other 
orders, being collected within a common involucre. To these Linneus 
added a sixth, Polygamia monogamia, wherein the flowers were not col- 
lected in a common involucrum ; but this last has been transferred to Pen- 
tandria monogynia. i aie 
In Gynandria, the orders are taken from the number of the stamens. 
- Moneecia and Dieecia, including plants that are monandrous, diandrous, 
monadelphous, or gynandrous, have the names of the orders, as Monandria, 
Decandria, Gynandria, taken from some of the preceding classes. The 
23rd class, or Polygamia, containing plants with bisexual and unisexual 
flowers, mixed either on the same or distinct individuals, has in consequence 
been divided into three orders: Moneecia, in which the flowers are bisexual 
and unisexual on the same individual; Diccia, where one bears the bi- 
sexual and another the unisexual blossoms of both kinds; and Treecia, where 
one has the bisexual, another the male, and a third the female flowers. 
Cryptogamia was originally divided by Linneus into four orders: Ferns, _ 
Mosses, Alge, and Fungi; but so little was then known about the struc- 
ture and limits of these, that it is now generally agreed to adopt nearly 
the same divisions as are employed in the natural method. 2 : 
