128 NATURAL METHODS. 



been placed. We thus form natural families. If the whole vegeta- 

 ble kingdom could thus be distributed into natural tribes, we should 

 need^o artificial system. But after selecting a few families, which 

 exhibit striking marks of resemblance, we find genera whose re- 

 lation to other genera seems doubtful or obscure, and at length find 

 a vast number of plants which seem to have few natural affinities 

 with any other. 



Among resemblances which gives rise to natural families, are, 

 1st, resemblance 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 infloresence, 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 classifi- 

 cation, it is necessary to observe many plants, and the most con- 

 stant characters of their organs. To find the place of plants in the 

 artificial classes and orders, it is only necessary to observe the dis- 

 tinctions of the stamens and pistils. 



The physician is chiefly conversant with the natural characters of 

 plants, especially with such as are connected by medicinal qualities; 

 he considers one group as narcotics ; another as tonics ; another as 

 stimulants, &c. 



The natural method depends for its utility, much upon the artifi- 

 cial system, which enables the student to ascertain the name of a 

 plant, and thus learn its place among the natural orders. For ex- 

 ample ; suppose that a person meets with the plant commonly call- 

 ed stramonium, and wishes to know its character; by the Linnean 

 System, he soon learns its botanical name. Datura; and this genus 

 he finds belongs to the natural order, Solanect, characterized b}' 

 qualities of an active and deleterious nature, as the Tobacco, Pox- 

 glove, &c. 



The experienced botanist is not always obliged to refer to the 

 artificial s}^stem for the natural character of an unknown plant 

 Being famiUar with the characteristics of the different families, he 

 can often determine at once by the habit or general appearance of 

 the plant that it belongs to the lily tribe (Liliacece,) to the mallows 

 tribe {Malvaceae^) to the wild turnip tribe (Aroidea:,) or to any other 

 of the conspicuous and well-defined natural orders or families. 



To Linnaeus belongs the honour of having first suggested the ar- 

 rangement of plants into natural orders. 



He published in 1738 what he modestly termed " Fragments of a 

 natural method," consisting of 58 orders, founded upon the resem- 

 blance of plants in their habits, general appearance, or medicinal 

 qualities. 



The most popular Natural method is that of Jussieu, a botanist of 

 Paris, improved by De Candolle of Geneva.* The characters em- 

 ployed in this method, are, 



1. T7te structure of the Seed, with respect to cotyledons. A plant 



* Professor Lindley of England, has recently published a work on the natural sys- 

 te m, which is deservedly popular. 



Resemblances which give rise to them— Physicians interested in the natural method 

 —Connexion between the natural and artificial methods— Experienced botanists 

 know plants by their habits— Natural method of Linnajus— Method of Jussieu— 

 What are the characters employed in Jussieu's method 7— How is the structure of tho 

 seed considered 1 



