20 MR. F. N. WILLIAMS ON THE GENUS SILENE, 
Rohrbach’s enumeration is desirable in the interest of accuracy 
of description, and with due regard to the affinities of allied 
species. Species described since the publication of Rohrbach’s 
work have been intercalated in their proper place, or (in many 
cases) reduced as synonyms or as varieties of previously known 
species. 
The matter under the head of each species is arranged as 
follows. The name of the species is followed by the authority 
for the name and the werk or memoir in which it was first 
published.* This is followed by the citation of a published 
figure of the plant, if a satisfactory one is known to me: the 
third reference is to the page of Rohrbach’s ‘ Monograph’ on 
which the species is described. The species described by 
Rohrbach have not been again described in this Revision, 
unless subsequent re-examination of specimens has obviously 
impaired the accuracy of Robrbach’s description ; slight varia- 
tions, discrepancy, or hiatus in his diagnosis have been noted 
and rectified in form of addenda after the references following 
the name. The species known and discovered subsequently to 
the publication of Rohrbach’s work have been described on a 
uniform plan, and as far as practicable the diagnoses are of 
uniform length and conciseness; and species which have been 
transferred to another group or section have not been re- 
described unless such transference has entailed considerable 
and important verbal alterations. After the description or 
bibliographical references are often given a few differential 
characters distinguishing it from allied forms, more particularly 
in subsidiary groups which include several species. The 
synonymy, in so far as it is identical with that given by 
Rohrbach, is omitted, but under this heading additional 
synonyms (reduction of new? species) are given, ard some 
synonyms, incorrectly given by Rohrbach, are excluded. This 
is occasionally followed by critical notes or explanatory com- 
ments on the species, where they may seem to be required. 
The last item under the heading of each species gives the limits 
of the geographical range. It has not been thought necessary 
to give the complete geographical distribution, as any extension 
of the range of the species as defined by Rohrbach is thus 
* For species described since 1868, references are sometimes given to 
two works in which a description of the species is to be found, as the 
publication in which a new species is first described is often inaccessible. 
