THE AMERICAN BOTANIST. 
59 
they appear to have all the characteristics of recognized 
species. They are not, however, the same as systematic 
species, and DeVries accordingly calls them elementary 
species. Such elementary species among our wild plants 
will at once come to mind. The white form of the closed 
gentian, the red flowered form of the horse gentian, the 
green stemmed form of the common elder, the 3^ellow 
berried holly and the many smooth forms of hairy species 
or the reverse may be cited as instances. Probably there 
is not a reader of these lines who has not at some time 
observed one or more of these elementary species. Several 
have been described in this magazine and wdien such forms 
become more familiar, elementary species hunting will 
become more fascinating than other plant collecting. One 
of the most astonishing facts brought out by the cultiva- 
tion of various plants is that many of them will produce 
the same mutations again and again indicating that the 
characters of the elementar3^ species are latent in the 
parent species. The closed gentian well illustrates this 
idea. In almost every locality where this plant grows 
some plants will be found bearing white flowers. These 
come true from seed and may also be produced by sowing 
seed of the blue form, each sowing being likely to produce 
a lew white flowered plants which thereafter are easily 
reproduced from seed. The ability to produce white 
flowers, then, is a latent character in the closed gentian. 
Not all species are supposed to produce mutations — only 
the younger and unfixed tA^pes are thought to do so — but 
in some species the mutations are numerous, in the case of 
Draba verna amounting to more than two hundred 
distinct forms. 
* * 
«■ 
It will thus be seen that the systematic species is 
regarded by DeVries as a composite of elementary species. 
Ordinarily the characters of the latter may be blended in 
a single individual of the systematic species but by culti- 
vation and selection each elementary species ma3^ be iso- 
lated. The reason we do not find man3^ of these elemen- 
