NATUKAI. METHODS. 
121 
lives generic names are nouns. The specific name sometimes indicates the num- 
ber of leaves, as orchis hifolia (two-leaved orchis) ; or the color of the corolla, as 
VIOLA tri-color (three-colored violet) ; or the form of the root, as solanum tuberosum 
[vf 'iih a tuberous root). Specific names are often derived from the names of per- 
sons : thus, a species of Origanum is named tournefortii, after its discoverer, Tour 
aefort. Generic names are commenced with a capital letter : specific names are 
not thus distinguished, but are usually in italics, being Latin words. 
151. After having analyzed a number of plants, the student 
will naturally begin to observe a striking resemblance in many 
genera, and arrange them in groups without any reference to 
the artificial class or order where they may have been placed. 
We thus form Natural families. K the whole vegetable king- 
dom could thus be distributed into natural tribes, we should 
need no artificial system. But we find genera whose relation 
to other genera seems doubtful or obscure, and there are many 
plants which seem to have few natural alliances with other 
plants. 
152. The reserriblances which give rise to natwal families^ 
are — ^resemblance in seeds ; in pericarps^ or the envelopes of 
seeds ; in stamens and pistils / in corollas and calyces / in the 
modes of inflorescence^ or the manner in which the flowers grow 
together upon the stalks ; in leaves / in roots; and in stems. The 
physician is chiefly conversant with the natural cha/racters of 
plants, especially with such as are connected by medicinal qual- 
ities ; he considers one group as narcotics / another as tonics / 
another as stimulants., &c. The natural method is aided by the 
artificial system ; this enables the student to ascertain the name 
of a plant, and thus learn its place among the natural orders. 
For example, suppose a person meets with the plant commonly 
called stramonium, and wishes to know its character ; by the 
Linngean System he soon learns its botanical ndimQ.^ Datura ; 
and this genus he finds belongs to the natural order, Solanacece^ 
characterized by qualities of an active and deleterious nature, as 
the Tobacco, Foxglove, &c. The experienced botanist can often 
determine at sight, by the habit or general appearance of the 
plant, to what tribe it belongs. 
153. Linnaeus published in 1738 what he modestly termed 
" Fragments of a natural method," consisting of 58 orders, 
founded upon the resemblance of plants in their habits, general 
appearance, or medicinal qualities. A popular I^atural method 
was, after this, proposed by Jussieu, a botanist of Paris, and this 
has been improved by De Candolle of Geneva, and by Lindley, 
Professor of Botany in the University of London. The charac- 
ters employed in this method are. The structure of the Seed., 
with respect to cotyledons; insertion of the Stamens / absence a/nd 
151, Natural families. — 152. Resemblances which give rise to natural families — Connection between 
the natural and artificial methods — Experienced botanists know plants by their habits. — 153. Natura. 
n«thod of Linnaius — Method of Jussieu — Characters employed in Jussieu'a method. 
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