1884.] Botany. 627 
prevail among all the veronicas, while vellow predominates in the 
St. Johnsworts, and white in the umbellates? These are the sort 
of questions which we must endeavor briefly to answer by the light 
of modern evolutionary biology, from the point of view of the 
function which each color specially subserves in the economy of 
the particular plant which displays it.” 
We should like to quote more from this fascinating little book, but 
enough has been given to make every reader wish to possess and 
read the whole book for himself. 
PG pe if we push our inquiry a step further back, we shall find 
| Par geet stocks, is true also of the parent stocks themselves in 
has been t from an earlier common ancestor. Each of them 
Qvoreg produced by the selective action of nature, which has 
yong certain individuals in the struggle for existence at the ex- 
Of new ene? and has thus finally resulted in the establishment 
now wane a having peculiar points of advantage of their own, 
iy are y distinct from the original species whose descendants 
ked at in this manner, every family of plants or 
Sme — omes a sort of puzzle for our ingenuity, as we can to 
Points nt reconstruct the family genealogy by noting in what 
tious members resemble one another, and in what 
“hot ae 
oy 
40 
