132 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
are within the genus, as here interpreted, three fairly distinct 
sections that from a narrower point of view might be considered 
separate genera. It is obviously necessary to locate that por- 
tion of the group that would retain the name Lesquerella were 
the sections elevated to generic rank. We must decide, if pos- 
sible, upon a type species for the genus. Unfortunately L. 
Lescuri (Britton & Brown, Ill. Fl., ed. 2, 2: 154. 1913) has 
been previously designated as the type species because it occu- 
pies first place in the original publication of Lesquerella. This 
was apparently done without due regard to the very reasons 
that placed it first in the list of species. The International 
Rules of Botanical Nomenclature adopted at Vienna in 1905 
are very clear as regards that portion of a genus that is to 
retain the original name. Article 45 reads in part: ' When a 
genus is divided into two or more genera, the name must be 
kept and given to one of the principal divisions. If a genus 
contains a section or some other division, which, judging by its 
name or its species, is the type or origin of the group, the name 
is reserved for that part of it." "The example for this point is 
taken from the genus Helianthemum. The genus contained 
originally nine sections; ‘‘several of these sections have since 
been raised to generic rank but the name Helianthemum has 
been kept for the divisions grouped round the section Euhelian- 
themum." In the original description Watson divided the 
genus into the sections ‘‘Alysmus’”’ and ''Lesquerella, proper." 
Probably because he regarded the first group as the more primi- 
tive as well as somewhat aberrant, he placed it first. The most 
aberrant species of all he placed first in the section. Of this 
species he said: ''Our one flat-podded species that has been 
referred to Alyssum (A. Lescurii) appears to differ in no other 
respect than its less convex valves from a somewhat distinct 
group of species which can be separated, however, only as a 
section from the rest." To accept this species as the type species 
of the genus would certainly be contrary to what the author 
had in mind when he described the genus. If the genus were 
divided, a step we would greatly deplore, the International Rules 
point definitely to the section ''Lesquerella proper," or ''Eules- 
querella," as the part that would retain the present generic 
name. From this section as outlined by Watson the type species 
