40 INTRODUCTION. 
and severances of the quasi-specific forms, he is too frequently left 
uncertain what is really intended by the names used. He is thus 
forced to go backward rather than forward, by keeping up the 
elder and larger aggregates, and by shunning the more recent and 
smaller segregates, while endeavouring to trace out the distribution 
of plants by examining those discordant sources of information. 
His motto must be “omne majus in se continet minus ;” for, in 
falling back upon the larger aggregate, all the records become 
available; while the further he gets forward to the newer and 
smaller segregates, the less available for his purposes do the past 
printed records become. In several instances in the prescut 
volume, two or more readily distinguishable segregates are un- 
avoidably treated together as one aggregate species, simply because 
the printed records of their localities would mostly be found non- 
available, in attempting to treat them apart. 
5. Rexation of VARIETIES TO SPECIES. 
The antecedent remarks on the different grades of species will 
have prepared us to see that no theoretic line of distinction is 
always practically available between Species and Varieties. That 
which is a good and true species, in the estimation of one botanist, 
is simply a variety of some other species, in the estimation of a 
second botanist; or, it may be held a sub-variety, by a third 
botanist ; even a sub-sub-variety, by a fourth botanist. Thus, to 
revert to the illustration on page 88, if Ranunculus aquatilis 
(Linn.) be accepted as the true species, then heterophyllus is one 
of the forms or varieties of that species, and floribundus is a 
secondary or sub-variety of the primary variety. And if, by any 
possible expression of technical characters, the floribundus itself 
could be further divided, any of its segregated parts would be in 
the position of tertiary or sub-sub-varieties to the Linnean species 
R. aquatilis ;— it even was so, without further subdivision, rela- 
tively to the very aggregate species, the Rununculus aquaticus of 
Bentham’s Handbook in its first edition. In the actual practice of 
technical botanists, let the student understand and remember, 
