[Vor. 11 
108 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
DISCUSSION OF THE SECTIONS 
In the preparation of this monograph more than seven thousand 
specimens of Mimulus have been carefully examined. Ав a 
result of this study the writer has been led to believe that the 
genus is most satisfactorily treated by dividing it into two 
subgenera with several sections under each. The species which 
Dr. Gray and many other systematists regarded as Mimulus 
proper or Eumimulus have been divided among four sections, 
based primarily on differences in the calyx and corolla. The 
members of these sections agree in having the placentae united 
firmly, forming a central column or separating only at the apex, 
rarely parting as far as the center. These sections form a sub- 
genus, Synplacus. The other sections, in which the placentae 
divide to the base, form the second subgenus, Schizoplacus. 
Through M. rubellus and some of its close relatives the two sub- 
genera intergrade, the placentae separating nearly half way to the 
base in these species. 
Synplacus can also be distinguished by its pedicels which are 
usually much longer than the calyx, its glabrous or puberulent 
style, its bilamellate stigma with nearly equal lips, and its mem- 
branaceous capsule which is dehiscent to the base along both 
sutures. The species in this subgenus have been arranged in four 
sections, Eumimulus, Erythranthe, Simiolus, and Paradanthus. 
Eumimulus was proposed as a section by Dr. Gray in his first 
revision of the genus in 1876. In it, he included not only the 
type species and its immediate allies but all of the species be- 
longing to the subgenus under discussion, Ентітшив is char- 
acterized by its tubular calyx with equal teeth, its distinctly 
bilabiate blue corolla without the hairy palatine ridges charac- 
teristic of Simiolus, and its placentae which separate at the apex. - 
One New Zealand species, M. linearis, varies in being an annual 
and in having exserted stamens. It was described by Robert 
Brown as the type species of the genus Uvedalia. However, 
when more material was collected the relationship between. 
Uvedalia and Mimulus became so obvious that the newly de- 
scribed genus was soon relegated to synonymy. do 
_Erythranthe эз a genus was based on the single species, M.car- | 
dinalis, the extreme bilabiate corolla, exserted style and stamens, | 
