924] 
GRANT—A MONOGRAPH OF THE GENUS MIMULUS 108 
Mountains, lists three species under Eunanus but the Mime- 
tanthe pilosa of Greene, he places under Mimulus as M. pilosus. 
Wettstein! considers that of all the segregates, only Mimetanthe 
is entitled to generic rank and he places it in a different group. 
GENERAL MORPHOLOGY 
Roots.—The root system in the genus Mimulus is not extensive, 
even in the shrubby forms. The majority of the species are 
annuals and have a simple annual root; this usually consisting 
of a short tap root with a few lateral ones or occasionally all of 
the roots are lateral. Many of the species are perennial by root- 
ing from the nodes, and if any of the stem touches the ground 
roots will develop at all the joints in contact with the moist earth. 
Whether plants of this type are truly perennial is doubtful; in 
protected places they may survive the mild winters in some 
parts of the world, but if in an exposed position, plants of the 
same species are typical annuals. 
Stems.—The stems vary greatly in the several groups from the 
dwarf subacaulescent members of (Enoe to those in Diplacus 
Which are woody and from six to eighteen decimeters high. The 
majority of the perennials die down during the winter, coming 
up each spring so that the parts above ground are mainly annual. 
The stems sometimes are simple but more commonly they are 
more or less branched. Тһе main axes and branches may be 
terete or quadrangular, terete stems being the more common. . 
M. ringens and M. alatus have square stems, those of M. alatus 
‚ being winged. 'The probable derivation of M. alatus from 
M. ringens is indicated by the fact that in the latter we occasion- 
ally find stems which are partly winged. In the section Simiolus 
the majority of the species have quadrangular stems, these often- 
times being hollow. | 
Underground stems are common in the perennial species. 
Most of the members of the sections Eumimulus, Erythranthe, and 
many of those in Paradanthus have horizontal stoloniferous root- 
Stocks growing not far below the surface. А few species, such 
as M. moschatus and M. Tilingi, have moniliform rootstocks. 
M. jungermannioides and M. primuloides commonly propagate 
! Wettstein, R., in Engler & Prantl, Nat. Pflanzenfam. 4%: 77. 1891. 
