Arrangements of Plants. 73 
secondary part of the system it will therefore scarcely be denied 
that the advantages of perspicuity and precision are wholly on 
the part of Linnzus, whatever may be the case as to the natural 
order of the plants; in which respect, however, it is by no means 
clear that Jussieu possesses any superiority over his predecessor. 
From classes and orders we descend to genera, in the deter- 
mination of which the chief difficulties of the science consist ; 
but as in some of the orders the number of genera is very great, 
it has been found indispensably necessary to divide such orders 
into sections, so as to place each genus in its proper relative 
situation, and break in as little as possible upon their natural 
or apparent affinities. ‘This Linnzus and his subsequent editors 
have endeavoured to do by a kind of collateral arrangement 
placed at the head of each class, though not strictly conformable 
to the rest of the system. For the discrimination of these sec- 
tions there remained ample materials. The stamina and pistils 
had indeed already been employed in characterizing the classes 
and orders ; but the corolla, as well with respect to the number 
of its petals as its form and situation, the calyx, the receptacle, 
the germen, the stigma and the fruit, all offered important marks 
of discrimination, which have been made use of so as greatly to 
assist the student, although not with all the beneficial effect that 
might have been expected, or so as to define with accuracy the 
relative situation of each genus. The same mode of dividing 
the orders into sections has also been resorted to by Jussieu; 
but as he had already employed the corolla and the situation 
of the stamina in order to characterize his classes, he has 
been obliged to have recourse in his subordinate divisions to 
other distinctions. -He therefore chiefly employs for this pur- 
pose the number of the stamina, and the style, with the addition 
of the receptacle, and particularly of the fruit. Thus it appears 
VOL. XI. L that 
