492 
sions, one of which has visible sexual parts (pha- 
nerogamous), while in the other they are invisible 
or wanting (cryptogamous). The first division 
comprehends the 23 first classes of his system, 
which are distinguished according to the situa- 
tion of the sexual parts in the same or in separate 
flowers, their number, their length, &c. If any 
system has introduced order in the midst of vari- 
ety, and shed light on the immense diversities of 
nature, it is that of Linnzeus. Hence, even those 
who have departed from it in their writings have 
considered it necessary for elementary instruc- 
tion. Many objections, however, are brought 
against it. It has been made a question whether 
it is fitted for the investigation and classification 
of unknown plants. It is said that the sexual 
parts may be very different in similar plants ; 
that he never will have a complete idea of nature 
who proceeds only on one principle. It has, 
therefore, been thought necessary to find a more 
natural arrangement. In order to follow nature, 
we must look at every part; at the internal 
structure, as well as the external relations, ana- 
logies, and differences. This can be done only 
by a profound and toilsome investigation, of 
which the mere follower of a system has hardly a 
notion. Seed is considered as the ultimate ob- 
ject of vegetation. Its parts, their formation, 
situation, and other relations, must be critically 
examined. The most perfect natural system, in 
modern times, is that of Jussieu, particularly as 
enlarged by Decandolle. 
The second general division of this science be- 
gins with the investigation of the internal struc- 
ture, or the anatomy of plants. This study has 
been recently cultivated, by the Germans, to an 
extent which, forty years ago, could hardly have 
been conceived. It is closely connected with the 
first division, if the plants are studied in their 
natural order. Without good microscopes, and 
the aid of the best works in this branch, a dis- 
tinct knowledge of the structure of plants cannot 
easily be obtained. Chemical botany must be 
connected with the anatomy of plants. Their 
constituent parts, their various changes, and the 
different combinations of their liquid and solid 
parts, are to be examined. From those we ascend 
to the laws of vegetable life, which are, in gene- 
ral, the same as those of animal life. Animal 
physiology must, therefore, be intimately united 
with the physiology of plants. Connected with 
the latter are two branches of knowledge, which 
the botanist cannot well dispense with, since 
they offer the most important conclusions on the 
economy of nature, on the history of the earth, 
and on the application of science to the arts. 
These are, first, the science of the deformities 
and diseases of plants, which can be made certain 
only by correct physiological views, and which 
is of great value in gardening, agriculture, and 
the cultivation of woods; and, second, a know- 
ledge of the mode in which plants have been 
spread over the earth. If we study the forms of 
BOTANY. 
vegetation which have come to us from distant 
ages, in the floetz formations, this observation af- 
fords the most interesting discoveries in relation 
to the history of our earth. If we trace the laws 
by which vegetation seems to have been distri- 
buted, we extend our knowledge of the general 
action of nature, and arrive at conclusions which 
may be of great practical utility. The work of 
Sprengel on the structure and nature of plants, 
is, perhaps, the most complete. Separate parts 
of the anatomy of plants have been treated of by 
Link, Treviranus, Moldenhawer, Keith, Ellis, and 
Mirbel; vegetable chemistry by Senebier, Saus- 
sure, Schrader, Liebig, Boussingault, and others. 
SystemMATIc Borany.—Systematic botany has 
been defined to be “the science of arranging 
plants in such a manner, that their names may be 
ascertained, their affinities determined, their true 
place in a natural system fixed, their sensible 
properties judged of, and their whole history 
elucidated with certainty and accuracy.” To 
facilitate the arrangement of plants according 
to their relationship, they are distributed into 
groups of higher or lower rank, the more general 
ones comprising the subordinate; species being 
brought together into genera or kinds, genera 
arranged under tribes or orders, and these under 
classes or more comprehensive divisions. 
A species, or particular sort, embraces all the 
individuals which, slightly differing perhaps in 
size, colour, or similar unimportant respects, yet 
resemble each other more closely than they do 
any other plants, so that they may be deemed, 
or proved to be the produce of a common parent: 
and the seeds which they bear will yield similar 
individuals. Two seeds, however, taken from 
the same pod, will in many cases produce flowers 
of a different colour, or with different markings; 
or will give rise, if grown in different situations, 
the one to a nearly smooth, the other to a hairy 
plant; the one to undivided, the other to lobed 
or cleft leaves, and to numberless similar diver- | 
These minor differences, not incompatible |. 
sities. 
with a common origin, but in fact tending to re- 
vert (at least in a natural state) to the type of 
the species, constitute varieties. 
A genus is an assemblage of nearly related 
species, agreeing with one another in general 
structure and appearance more closely than they 
accord with any different species. Thus, the 
sweet-brier, the dog-rose, French rose, cinnamon 
rose, and others, constitute the universally-re- 
cognised genus Rosa; the various species of rasp- 
berry and blackberry compose the genus Rubus ; 
the apple, pear, &c., the genus called by botanists 
Pyrus: so the different oaks, willows, poplars, 
birches, &c., form as many separate genera. 
When two or more species of a genus resemble 
each other in particular points more nearly than 
they do the other species, intermediate sections 
are often recognised; which, when well marked 
by characters of considerable importance, receive 
the title of subgenera. : 
