126 
CHARACTERS USED IN CLASSIFICATION. 
of facts. Positive cha/racters are constant or inconstant ; — all 
seeds produced by plants of the same species have the same 
structure ; 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 odor offer inconstant characters. 
160. AU real science in Botany must rest lijpon cmistant char- 
acters i therefore these characters are much more important 
than the others. Constant characters may he isolated or coexist- 
ent. The petals of the ranunculus acris (butter-cup) have a 
gland 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 Campanula rotundifo- 
lia (blue-bell) adheres to the ovary ; this must of necessity be 
simple, or without divisions, and the corolla and stamens at- 
tached to the interior of the calyx. The character of the ad- 
herence of the calyx to the ovary brings in its train several 
other characteristics ; it is then coexistent.^ and is more import- 
ant than the isolated character. 
161. Two orders of characters are deri/ced from the two great 
divisions of vegetable organs — those of vegetation and rejproduc- 
tion. The cha/racters of reproduction are numerous and often 
coexistent; one cha/racter serving as an index to many others. 
It is seldom that plants which resemhle each other in their 
characters of rejpi^oduction differ much in their cha/racters of 
vegetation. For example, all plants with four didynamous 
stamens attached to a monopetalous, labiate corolla, and four 
seeds lying uncovered in a monophyllous calyx, have an angu- 
lar stem, and opposite leaves. On the contrary, it frequently 
happens that plamts which resemble each other hy the characters 
of vegetation.) differ hy those of reproduction. Labiate and 
caryophyllous plants agree in hoA^ing their leaves opposite., and 
yet there is no resemblance in their fowers. This considera- 
tion alone would seem sufficient for establishing the superior 
importance of the characters of reproduction over those w vege- 
tation. The seed tmites in itself the characters hoth of repro- 
duction and vegetation. The embryo is the commencement of 
tlie new plant, and it offers us the first characters of vegetation ; 
but its situation in the fruit, the number, form, and con- 
si'Stence of its envelope, are cha/racters which belong tofructificor 
tion. 
Different kinds of positive characters.— 160. Constant characters, of what kinds 7—161. Character! 
>f reproduction and vegetation. 
