Arrangements of Plants. 71 
tion of a long definition for an appropriate appellation, the con- 
sequence of this diversity in the two systems is in other respects 
important. The separation of the vegetable kingdom into classes 
is only one stép towards an arrangement. "The subordinate 
divisions of orders and ‘genera require other distinctions. Tt 
becomes necessary, therefore, not to expend, as it were, in the 
formation of the classes those peculiarities which may be applied 
with so much effect, and which are indeed indispensable in the 
subordinate arrangements. Of this Linnzus was fully aware ; 
and he has accordingly reserved for this purpose, not only certain 
particularities in the situation of the stamina, but the whole 
advantages arising from the corolla, calyx, and nectarium : and, 
what is of still greater moment, the distinctions dependent on the 
number and form of the style and stigma. Jussieu, on the con- 
trary, has prematurely deprived himself of many of these distinc- 
tive characters, although from the greater magnitude of his 
classes he has greater occasion for them. Those which arise 
from the number of the petals, as well as the situation of the 
stamina, he has applied to the formation of his classes, and in 
some instances, as in his tenth and eleventh classes, has even 
resorted to the antherz for these leading distinctions. ‘The con- 
sequences of this will more fully appear by a brief comparison 
of these arrangements in their subordinate divisions. 
According to each of these systems, the classes are divided. 
into orders. Linnzeus, still aiming at simplicity, but founding 
his decisions on strong natural distinctions, has for this purpose 
recourse to the pistillum, or style, the immediate organ of im- 
pregnation, and essential to the formation of the fruit. Asa 
single word has expressed the class, so another word now gives us 
the order ; and to a practical botanist the expression Pentandria 
monogynia suggests the idea of a division of plants including, 
| among 
