on the works of creation, whence must arise senti- 
ments the most elevated, and gratitude without 
alloy, to the Omnicient Creator of them all, for the 
abundance of His undeserved mercies. 
In this plant, as in many others, we see what 
Linneus calls the sleep of plants, that is, the falling 
together of the leaflets, intended, evidently for pur- 
j)oses on which we can only speculate. We know, 
however, that one great use of the leaves is for the 
exposure of the sap to the influence of the air, heat, 
and light; and that, as is observed by Sir H. Davy, 
'Hn the leaves much of the water of the sap is 
evaporated; it is combined with new principles, 
and fitted for its organizing functions, and probably 
passes in its prepared state from the extreme tubes 
of the alburnum into the ramifications of the cor- 
tical tubes, and then descends through the bark. 
On the upper surface of leaves, which is exposed 
to the sun, the epidermis is thick but transparent, 
and is composed of matter possessed of little organi- 
zation. By these arrangements any evaporation, 
except from the appropriate tubes, is prevented. 
On the lower surface, the epidermis is a thin trans- 
parent membrane, full of cavities, and it is pro- 
bably altogether by this surface that moisture, and 
the principles of the atmosphere necessary to vege- 
tation, are absorbed.” Hence, we may catch a 
glimpse of the economy of nature, and perceive 
that cogent reasons doubtless exist for the peculiar 
action of leaves which we have noticed. 
The Oxalis tetraphylla is a neat plant, and its 
flowers lively. It is quite hardy, and increases 
freely at the root. 
Don’s Syst. Bot. 1, 760. 
