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CHARACTERS USED IN CLASSIFICATION. 
philosophy, to suffer hypothetical reasoning to usurp the 
place of direct observation of facts. 
5th. Positive characters are constant or inconstant. All seeds 
produced by plants of the same species have the same struct- 
ure; all plants which grow from these seeds, produce other 
seeds, similar to those from which they have had their 
origin : of course the characters derived from the structure 
of these seeds are constant. But among these plants some 
are large and others small ; some may have white corollas, 
some, red, or blue ; some are more fragrant than others ; 
of course, size, color and odour offer inconstant char- 
acters. 
6th All real science in botany must rest upon constant charac- 
ters ; thei efore, these characters are much more impor- 
tant than the others. 
7th. Constant characters may be isolated or coexistent. The 
petals of the ranunculus acris (butter-cup) have a necta- 
ry in the form of a scale ; this character, although constant 
is isolated, for it is not necessarily connected with any 
other characteristic trait. The calyx of the c ompanula 
rotundifolia, (blue-bell,) adheres to the germ ; the germ 
must of necessity be simple or without divisions, and the 
corolla and stamens attached to the interior of the calyx. 
The character of the adherence of the calyx to the germ, 
brings in its train, several other characteristics ; it is then 
coexistent ; and is more important than the isolated char- 
acter. 
8th. Two orders of characters are derived from the two great 
divisions of vegetable organs ; those of vegetation and 
reproduction. The characters of vegetation are few, and 
mostly isolated; the characters of reproduction are nu- 
merous and often coexistent ; one character often serving 
as an index to many others. 
It is seldom that plants which resemble each other in 
their characters of reproduction, differ much in their char- 
acters of vegetation. For example, all plants which have 
four didynamous stamens, attached to a monopetalous labi- 
ate corolla, and four seeds lying uncovered in a mono- 
phyllous calyx, have an angular stem and opposite leaves. 
On the contrary it frequently happens, that plants which re- 
semble each other by the characters of vegetation, differ 
by those of fructification. Labiate and caryophyllous plants 
Positive characters constant or inconstant — Constant characters may 
be isolated or coexistent— These terms illustrated — Two orders derived from 
reproduction and vegetation — 
