INTRODUCTION. 11 
given genus in different portions of its range is indicated and 
the general generic range is briefly given. This compilation 
permits the student to see at once in which portion of its gen- 
eral range any given genus is preponderantly developed, and 
to compare the relative development of allied or distant groups. 
Citation of authors of genera and species. In order to ob- 
tain stability of nomenclature it is necessary to provide that the 
name of a plant, the specific name, can not be changed through 
caprice or whim. Nor can it be changed through ignorance, 
providing the mistake through which the change was made has 
been discovered. The refusal to correct mistakes and the dis- 
inclination to do thorough bibliographical work before publish- 
ing a new specific name is the cause of most confusion in botan- 
ical nomenclature. Hence has arisen the so-called international 
law or law of priority which provides that the earliest pub- 
lished specific name of any plant must stand providing that 
name is not antedated by some other similar name applied to a 
plant belonging in the same genus. Many botanists do not 
admit the validity of this principle except in the case of species 
which they may have themselves named and published. With 
reference to others they are accustomed to insist that ‘‘cus- 
tom,” ‘‘long-established-habit” and a conservative condition 
must be maintained. This is to save the difficulty of having to 
revise their own systems of nomenclature, and serves in many 
cases to cover inaccuracies or hastiness. With this conservative 
position, the unthinking and unbotanical are always distinctly 
satisfied and are accustomed to declare that botanical nomen- 
clature is purely a ‘‘ practical matter’ and should be taken out 
of the hands of the botanists altogether and turned over to 
some unprofessional commission for settlement (5). Objec- 
tions of this sort are natural, for the changing of names in 
our accustomed department of science is always a confusing 
matter. Such criticism is, however, unthinking and unbotan- 
ical because it fails to recognise that the whole difficulty has 
originated on account of just such conditions as are extolled 
and recommended for perpetuation. The only way to obtain a 
stable nomenclature is by rigidly enforcing the law of priority 
with reference to specific names. All instability finds its well 
spring in the disregard of this law, and stability under our 
present general system of nomenclature can only be obtained 
by strict adherence to the oldest available specific name, by 
whomever or wherever it may have been published. 
(5) Rand: Bot. Gazette, XVI. 318-319 (1891). 
