6 4 
NATURE NOTES. 
Species, botanists were little troubled with this question, and 
all that was thought necessary to constitute a botanist in former 
days was the knowledge of species. But now, since Mr. Darwin 
brought evolution to the front, the great question is, “ How have 
the morphological characters by which a species is known come 
into existence ?” Even he himself did not lay himself out to 
discover these hidden secrets of nature, but rather took up a 
position which might be expressed by saying, “ Give me varia- 
tions of structure, and I will then explain how nature converts 
them into specific characters by natural selection.” 
At the present time, however, the attention of biologists is 
rather turned in the direction of trying to discover how varia- 
tions themselves first arise. This is a preliminary question 
which really ought to be answered before that of natural selec- 
tion be raised at all. 
Mr. Darwin tells us that varieties are incipient species, and 
as a variety only differs from a species by having a less number 
of differences from the type, the question resolves itself into, 
How do the different characters — often very slight — arise which 
mark any variety amongst plants ? 
It will be as well to illustrate this question by examples. I 
will take two cases from the Students' Flora, and we shall then 
be able to see on what principles a species becomes recognis- 
able as such and distinct from a variety. 
The first pair of species for comparison shall be distin- 
guished mainly by the details of their flowers, viz., Geranium 
molle and G. rotundi folium. A second pair shall be of the genus 
Salix, viz., S. herbacea and 5 . reticulata, as the species of willow 
are mainly distinguished by their vegetative system. 
In both cases we shall find that the characters taken singly 
are of no greater value than varietal or subspecific ; but being 
taken collectively the group elevates the plant to the rank of 
species. 
The comparable characters given of the Geraniums are as 
follows (i) G. molle, softly hairy; (2) G. votundifolium, laxly 
hairy; (1) petals notched, (2) entire; (1) claw bearded, (2) 
naked; (1) carpels wrinkled, glabrous, (2) not wrinkled, hairy ; 
(1) seeds smooth, (2) pitted. 
As examples of these characters, being taken as varietal or 
subspecific, are the following : — Sagina apetala, subsp. ciliata, 
glandular-pubescent ; subsp. mariiima, glabrous. Indeed, so 
variable are the degrees of hairiness in plants, that a species, 
Solatium nigrum, e.g., is described as both glabrous and pubescent. 
Silene gallica, petals 2-fid ; var. quinque-vulnera, petals entirq. 
Polygala vulgaris, subsp. depressa, var. ciliata, pedicels, bracts, 
sepals and capsule, ciliate ; subsp. oxyptera, pedicels, &c., 
glabrous. Lepidium campestre, pod papillose, subsp. Smithii, pod 
nearly smooth. Spergularia salina, seeds smooth ; var. neglecta, 
seeds papillose. 
(1) Salix herbacea , leaves oblong or orbicular, (2) S. reticulata, 
