CLASSIFICATION. 13: 
necessary in a species that it remain always the same 
from seed. A Variety, (varictas), is a species that 
differs only in colour, size, or in some accidental 
circumstance. From the seed the variety changes 
at last into the ‘true species. Of this» more (im 
§ 182. 
§ 124. 
From a good system we ey thatithe part se- 
lected, (eran to which. the classes, orders and 
_ genera are framed, shall be-easily seen, and without 
difficulty found; and that it shall be common to all 
plants, and not subject to variation. . Besides, no 
system ought to be divided according to pe other 
character than that first selected... No good system 
should have too many subdivisions, and, i possible, 
should only consist of classes and orders, The 
orders should) likewise..be founded only on one 
part. 
§ 125. 
For a beginner it is very convenient to be ac- 
quainted with several systems, cepaellye iviat the 
same time he knows the defects of each, that he 
may be able, by his own experience, to have re- 
course to that which particularly suits bim. I shall 
here give a view of the principal systems, m the 
language in which they were originally written ; and 
sHowies any term occur which is not to be caus 
in the preceding Terminology, 1 shall briefly ex- 
plain it. 
ie § 126, 
