PR1NCIPIA BOTANICA. 
No part of natural history hath employed* the pens -of so 
many writers, as the science of botany, in order to distin¬ 
guish and methodize the great variety of plants. 
The systems most in esteem for this purpose, before Lin¬ 
naeus, were those of Ray and Tourriefort. Ray is said to 
have described 18655 species, including varieties; and his 
method of arrangement was founded upon the general habit 
or structure of plants, their growth, as trees, herbs, &c. their 
greater or less degree of perfection, the number of petals, 
seed-leaves, and various other circumstances, which he arran? 
ged in 33 classes. 
Tournefort’s method is chiefly founded upon the figure oi 
the petals, which is preferable in that respect to others, figure 
being more constant than number: His classes are 22, sub¬ 
divided into 698 genera, which are again subdivided into 
30146 species and varieties. 
But the SEXUAL SYSTEM of Linnjeus hath now super¬ 
seded all others, by its concise and elegant arrangement, and 
by shewing the great analogy and nice connexion between 
plants and animals: It is founded on the difference in the 
sexes * of plants, and is divided into 24 classes, which are 
* The ancients, as Theophrastus, Dioscorides, Aristotle, Herodotus, and Pliny, 
as well as the modern botanists, were well aware of the sexes in many plants, and 
thence concluded it might be the same in all; but the full investigation, and 
classing them according to their sexes, was reserved for Linnaeus. 
B 
