1924] 
GRANT—A MONOGRAPH OF THE GENUS MIMULUS 111 
placentae are united into a central column separating at the apex 
or, in а few species, divided to the center. These points of 
similarity form the characteristics of Paradanthus, the fourth 
section. Possibly it will be conducive to taxonomic clearness to 
consider in greater detail these small groups. 
Mimulus rubellus is the center of an assemblage of fairly closely 
related species. Nearly allied to this species is М. Breweri, 
developing parallel to Еипатив as shown by its general glandular- 
pubescence, its glandular-pubescent style, and its pedicels 
which are longer or shorter than the flowers. M. Suksdorfii, like 
M. rubellus, is almost glabrous. The two species differ only in 
minor details, and it is possible that M. Suksdorfii has been de- 
rived from M. rubellus. М. deflexus is а larger-flowered species 
with a reddish-purple and yellow corolla which is connected with 
M. montioides through M. discolor. M. exiguus is, at best, 
distantly related to this group, its weakly angled calyx setting 
it aside from the others. 
It is possible that the six members of the M. Palmeri group 
have originated from species similar to M. rubellus; M. gracilipes, 
having the placentae divided about one-third of their length, 
might be an intermediate species between the two groups. 
M. Palmeri is the most widely distributed species although its 
diversity in color patterns suggests а recent origin. More 
material may show M. filicaulis to be only one of these color 
forms. M. androsaceus and M. purpureus are small plants with 
elongated pedicels; M. androsaceus, because of its less branched 
habit, probably being the older form. М. Bioleiti and M. 
icolor have been derived possibly from near M. Palmeri. These 
Species agree in having distinctly corky calyx-ribs. M. bicolor 
has a bilabiate corolla, this condition being poorly developed in 
M. Bioletti. e 
M. nepalensis and М. Bodinieri, two Asiatic species closely 
allied to each other, suggest relationship to М. inconspicuus 
because of the inflated calyces and small corollas. 
The prostratus alliance is composed of three species from 
Australia and one from India, all of which are perennials with 
thick, more or less succulent leaves and blue irregular corollas. 
M. repens has a personate corolla suggesting a possible evolution 
