240 
HAROLD’S DISCUSSIONS. 
of the leaves, which are usually three-lobed. The 
aquatic species has the immersed leaves cleft by 
thread-like divisions, while the upper leaves, which 
grow out of the water, are lobed or rounded, much 
like those on the dry ground. Did not these two 
species have a common ancestor, and the one taking 
to the water become differentiated into a new species ? 
We may conclude that the aquatic buttercup has taken 
to the water but recently, and is only partially adapted 
to aquatic life, for it is obliged to ripen its seed above 
the surface. On the other hand, the water-lily, in 
stem, leaves, and the manner of ripening its seeds, is 
perfectly adapted to aquatic existence. 
Birches develop into goodly trees in the valley, 
but on mountains and in the far north they remain 
small bushes; still farther north, where growth must 
be completed in a few months, they are very short. 
The smallest variety, known as the ‘‘dog-ears,” at¬ 
tains a height of less than one inch, and has but three 
leaves and a single catkin. It leaves in June, blos¬ 
soms in July, and fruits in August. It is the Lap 
among trees. 
It is well known that fruit-trees sometimes blos¬ 
som a second time when the fall has been unusually 
warm for a few weeks. Vegetables, particularly 
potatoes, deteriorate in quality if the growing season 
be a wet one. In swampy ground we find plants with 
broad or round leaves. The prairies abound in 
thrifty, well-rooted grass, the western slopes have 
their buffalo-grass, and Arizona grows its singular 
cactus-trees and sage-brushes. 
