INTRODUCTION. 
Xlll 
The hemp and fig tree are ex- 
amples of this order. 
54 Miscellaneee, consist of snch genera as 
are not connected together bj 
very numerous relations. 
55. Filices, ferns, bear their flower and 
fruit on the back of the leaf. 
5G. Musci. Mosses. 
57. Alg(B, flags, consist of marine plants 
whose root-leaf and stem are 
all one. 
58. Fungi. The mushroom tribe. 
Such are the natural orders of Liiinjeus, and it now remains 
for us to give some explanation of the System of Jussieu, as it 
is at present used by many botanists, in preference to that of 
Linnaeus. This system is said to have orig-inated in France, 
Avith Bernard de Jussieu, about the year 1758, but since that 
time it has undergone many modifications. The mode of 
arrangement and analysis are these : the vegetable kingdom is 
divided into three portions, according to the structure of the 
embryo and of vegetation, viz. 
1. DicoTYLEDONEs wliich are formed with two cotyledones, 
and whose vegetation is produced by the gradual superposition 
of internal layers beneath the bark ; these constitute the 
greatest part of the vegetable kingdom, and are deemed to be 
in a more |)erfect state of developement than the other two. 
They are subdivided, 1st, according to the number or absence 
of their petals, into Polypetalous, Monopetalous, and Apeta- 
lous ; 2nd, according to the insertion of their stamens which is 
Hypogynous or Perigynous; 3rd, according to the adhesion 
or non-adhesion of their calyx with the ovarium, which is 
either superior or inferior ; 4th, according to the position of 
the stamens with respect to the petals ; 5th, according to the 
structure of the fruit ; fith, according to the structure of the 
seed; and 7th, according to the modifications of their vegeta- 
tion, as far as they indicate a corresponding peculiarity in 
the parts of fructification. 2. Monocotyledon fs, whose em- 
bryo has one cotyledon, rarely more, and which in that case, 
germinates from a determinate point, and whose vegetation is 
formed by increase at their centre, not at their circumference. 
This order is also subdivided like the 1st, as far as it is appli- 
cable to them, but its |)rincipal section is that of Cryptogamia, 
which is charactei ised by the absence of any apparent flowers. 
3. AcoTYLEDONES, which contains the plants of the simplest 
structure ; have no sexes, but reproduce themselves by what 
are called sporles, that is, seed-like bodies, but differ from 
seeds, by germinating from any part of their surface, and in 
