34 
NATURAL ORDERS OF LINN.EUS AND JUSSIEU. 
LECTURE V. 
Condensed view of the Natural orders of Linnceus and Jussieu. 
Often when you have analyzed a number of plants you will 
begin to observe a striking resemblance to each other in many 
genera, and your own minds wrnuld suggest the propriety of 
arranging them into groups, without any reference to the ar- 
tificial class or order where they may have been placed. This 
is to form, what are called natural families. 
Among resemblances which give rise to natural families ; are, 
1st, In seeds. 
2d, In pericarps, or the envelopes of seeds. 
3d, In stamens and pistils. 
4th, In corollas and calyxes. 
5th, In the modes of inflorescence, or the manner in which the 
flowers grow together upon the stalks. 
6th, In leaves. 
7th, In roots and stems. 
In order to form a correct idea of the natural methods of 
classification, it is necessary to observe many plants, and the 
most constant characters of most of their organs. To find the 
place of plants in the artificial classes and orders, it is only 
necessary to observe the distinctions of the stamens and pistils. 
You will recollect that Natural Methods depend on many 
considerations ; the Artificial System is founded on a few sim- 
ple principles. 
But without attempting to explain to you the peculiarities of 
Natural Methods, we will now place before you those of Linnaeus 
and of Jussieu, a French botanist. These you are to refer to, 
in your analysis of flowers, rather than to study them in regular 
order. The physician is chiefly conversant with the natural 
characters of plants, especially with such as are connected by 
medicinal qualities ; he would say of such a group, this con- 
tains plants which are narcotic ; of another, these are tonics ; 
of another that they are refrigerants * &c. 
Yet though the natural method is of the greatest utility, its 
chief use depends on a knowledge of the artificial system, which 
enables us to find, in an expeditious manner, the name of the 
plant, and then its place among the natural families or orders. 
Linnaeus did not consider that his natural method could be used 
without the assistance of the artificial system ; but he considered 
the former as ingrafted upon the latter. 
* In explanation of these terms, see vocabulary. 
Arrangement of plants into natural families — Important resemblance* 
which give rise to natural families — Difference between natural methods 
and the artificial system. The physician chiefly conversant with natural 
methods. — 
