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Mp2 238° ss tructural wy PI ysiologtcal Botany, i yy jaz 
oe organs of reproduction—the parts of the flower, ‘Becdae tee e 
spores, &c.—form together a Genus. ‘The different species _ 
belonging to the same genus may differ very considerably 
in their vegetative organs ; but the slighter these differences 
the more natural is the genus, 
Since the time of Linnzeus two names have been given 
' to every plant, a generic and a specific name, the generic 
name being placed first, and the specific name last. Thus 
the cucumber is Cucumzs sativus, the melon Cucumis melo, 
both belonging to the genus Cucumis. 
Since the conception of a genus is defined arbitrarily, according to 
the individual view of each naturalist, and that of a species is no more 
natural, it has come to pass in the course of time that one and the same 
plant has received several specific and generic names, or that the same 
name, has been given to different plants. In order to distinguish clearly 
the particular plant meant, it is usual to append to its name that of the 
botanist who first bestowed it. Thus by the phrase Conitum maculatum 
Linn., is meant that Linnzeus was the first to give this name to the com- 
mon hemlock. In the present work the name of the authority will not 
be given, because only those plants will be mentioned with respect to 
which there will be little danger of a mistake as to the species intended. 
For the purpose of obtaining a general view of the enor- 
mous number of plants, and their mutual similarities or re- 
lationships, their classification into genera is not sufficient. 
Those genera which are nearly related, z.e. which resemble 
one another in the form and mode of arrangement of their 
organs of reproduction, are collected into Families ; these 
into Orders ; and these again into Classes. Several classes 
go to make up a Swb-kingdom, and the whole collection of 
sub-kingdoms constitutes the Vegetable Kingdom. Since, 
_ where the relationships are complicated, it is often neces- 
sary to distinguish steps even intermediate between these, 
it is usual to arrange the orders which make, up a class into ~ 
Series, the genera which make up a family into Zrzdes, and 
the species which make up a genus into Sections. “To de- 
note still further sub-divisions, the prefix ‘sub’ may be 
placed Lefore any of the terms mentioned, so as to mark 
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