GENERIC DISTINCTIONS IN PLANTS. 
63 
NATURAL HISTORY. 
Article VII.—GENERIC DISTINCTIONS IN PLANTS. 
The generic distinctions of plants according to the Linnsen or Sexual 
System, are regulated by the fructification. The parts known to early 
Botanists were few, and might be well thought insufficient for distin¬ 
guishing the various productions of nature. They, therefore, had re¬ 
course to the habit of plants, and other circumstances, for substitutes, 
and by this means a greater number of genera were established, which 
the new system is forced to reject. ' The fructification being admitted 
as the only sure foundation of the generic distinctions, all vegetables 
that agree in their parts of fructification, are to be put together under 
one genus, and all such as differ in those parts are to be divided. The 
characteristic part of each genus is to be fixed from the number, 
figure, proportion, and situation of all the parts; but as there are few 
genera, wherein all the parts are constant in every one of the species, 
recourse must be had to some one single circumstance that is con¬ 
stant, and make it the essential character. This in most genera may 
be found. The distinguishing part of Alyssum lies in the denticles 
of the stamina; in Bignonia, a mutilate stamen; in Ranunculus, it 
is the nectary which is a pore in the claws of its petals; in Hydro- 
phyllum, by the same, though a closed chink in the lacinae of the 
corrolla ; in Helleborus, by its being tubulose ; in Pancrantium, the 
stamens are inserted into the nectarium; in Hyoscyam, as there is a 
covering to the capsules; in Reseda, a lateral nectarium, but varies 
in its corolla and pistillum. The Campanula has a quinquevalved 
nectarium, but it is inconstant in its corolla and capsule; and lastly, 
in Iris has a stigma of singular construction, but varies in the beard 
of its corolla. There is, however, one part of fructification that can 
be relied on as a constant characteristic mark for all genera, it being 
found that the part which is constant in some genera, will be incon¬ 
stant in others. Thus in Carica, the flowers of the male part are 
monopetalous, and those of the female pentepatalous; in Myrica, 
some species have naked seeds, others berries; in Fraxinus, some 
have a naked flower and others a corolla: in Geranium, some have a 
regular corolla, others irregular; in Linura, some are pentapetalous, 
others tetrapetalous ; in Aconitum, some are tricapsular, others quin- 
quecapsular; and in Trifolium, some are monopetalous, others poly- 
petalous, some monospermous, others polyspermous. This incon¬ 
stancy of particular parts of many genera has been another source of 
error in the earlier Botanists, who have parted many plants from 
