vi ENGLISH BOTANY. 
There can be no doubt that these sub-species are well deserving 
of attention, and no reason can be assigned for neglecting them 
that would not apply equally to rejecting the examination of 
species, and confining the attention to genera or even natural 
orders alone. 
It is, however, often extremely difficult to decide whether a 
certain form ought to be regarded as a species or a sub-species ; 
occasionally, in a work on descriptive Botany, what are admitted 
as true species will be found to be quite as closely allied to each 
other as two other forms which the same author regards as 
mere varieties (sub-species in the present work). In fact, all 
botanists are guided in this matter by an imperfect kind of 
judgment, which is sometimes not far removed from caprice; 
and the present writer feels that he forms no exception to the 
general rule; indeed, no canons can be laid down that would be 
practically of much use in the very cases where they are most 
required. 
Mr. Watson, in his fourth volume of the “ Cybele Britannica,” 
suggests three terms,—ver-species, super-species, and sub-species. 
By the first of these, he intends the ordinary well-defined and 
generally adopted species ; by sub-species, those more obscure groups 
of forms, which differ from ver-species only in having the distine- 
tions between themselves slighter, or less generally recognized, or 
in apparently shading off more gradually into one another; and 
by super-species, the groups formed by uniting a number of sub- 
species, and which consequently include a greater variety of forms 
within their limits than is comprehended under the idea of a 
ver-species. 
The veal point of difference between botanists is, that some 
give the name of species to ver-species and super-species, while 
others apply it to ver-species and sub-species. But as no distinct 
line of demarcation can be drawn between ver-species and super- 
species on the one hand, and between ver-species and sub-species 
