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PART III. 
CliASSIFICATIOM. 
LECTURE XXI 
METHOD OF TOURNEFORT — SYSTEM OF LINN^US — NATURAL METHODS — METH- 
OD OF JUSSIEU — COMPARISON BETWEEN THE CLASSIFICATIONS OF TOURNE- 
FORT, LINNJ2US, AND JUSSIEU. 
Let us now imagine tlie whole vegetable kingdom, comprising ii^- I 
numerable millions of individual plants, to be spread out before a j 
botanist. Could he, in the course of the longest hfe, number each [ 
blade of grass, each little moss, each shrub, or even each tree? If j 
he could not even .count them, much less could he give to each one a 
separate 7iame -and desc7'iption. But he does not need to name them 
separately, because that nature has arranged them into 5or^5 or j 
kinds. : 
Were you sent into the fields to gather fiowers of a similar kind, 
you would need no book to direct you to put into one parcel, all the 
red clover blossoms, and into another, the white clover ; while the 
dandelions would form another group. These all constitute differ- 
ent species. Nature would also teach you that the red and white clo- 
ver, although differing from each other in some particulars, yet bear 
a strong resemblance. By placing them together you form a genus, 
and to this genus you refer all the different kinds or species of clover, j 
When you see the common red, damask, and cinnamon roses, you i 
])erceive they all have such strong marks of resemblance as to en- \ 
- title them to be placed together in one gen as. But yet you know 
that the seed of a flamask rose would never produce a red rose. | 
One species of plants can never produce another species. I 
The whole number of species of plants, which have been named j 
and described, including many which have been recently discover- [ 
ed in New Holland, and about the Cape of Good Hope, is said to j 
be 56,000.* 
If species of plants were described without any regular order, we ,, | 
could derive neither pleasure nor advantage from the study of prac- f 
tical botany. ¥/hen we wished to find the name of a plant, we ' 
should be obliged to turn over the leaves of our books without any 
rule to guide us in the search. 
The necessity of some kind of system was so apparent, that many 
attempts for the methodical arrangement of plants were made be- 
fore the time of Linnseus; but his system was so superior to all oth- 
ers, that it was no sooner published to the world, than it was adopt- 
ed by the universal consent of all men of science. 
Previous to this time, Tournefort, a native of France, had pub- 
lished an ingenious method, of arrangement, beautiful by its simpli- 
city, but imperfect, on account of the vagueness of its application. 
The characters of his classes were founded upon the absence, pres- 
ence, a,nd form of the corolla. Tournefort made twenty-two classes ; 
these he subdivided into sections or orders. 
* As recently reported by the Baron Humboldt, to the French National Institute. 
Nature arranges plants into kinds or sorts — Examples — Number of species of 
plants — Necessity of order in description — Attempts at arrangement made before the 
time of Linna3U3 — Tournefort's classes^ on what founded? 
