GARDENING AS A SCIENCE. 
83 
It is necessary to premise, agreeably to a former intimation, that, in plants with 
one seed-lobe, (monocotyledons, or Endogens^) the veins are continued in parallel 
lines from the base or leafstalk to the point. Corn, grass, lilies, orchis, furnish 
examples, and in these the stomates are easily detected, and in general they appear 
to be seated between the veins, as seen at No. 1 ; the subject investigated was 
a Lilium. 
1 2 3 
No. 2 is designed to represent the wavy net work of the veins in Zea rnays ; the 
drawings are usually exaggerated. 
No. 3 represents the irregular processes and inosculations of some plant of the 
great Exogenous class wherein the seeds have two lobes, and the leaves admit of 
multiform variations. 
We may believe that the leaves contain bundles of air and sap-vessels ; but here, 
as in vegetable structure generally, the cellular tissue is presumed to be the chief 
organ of fluid development and secretion ; and as the pores are connected with that 
system, it is likely that they transpire as well as absorb, and thus keep up a 
perpetual intercourse with the atmosphere, and this is partially proved by a 
very simple experiment which some will have an opportunity to observe. Our 
recital shall be one of facts which actually occurred. 
In a house — first built for vines, therefore not capacious in height — a plant of 
Musa coccinea was grown, and flourished luxuriantly. It reached the glass, 
overtopped a vine, and shaded some of its leaves. "When the sun shone powerfully 
in the forenoon, drops of water were formed upon the vine-leaves shaded by, and 
in close contact with, Musa, the upper surfaces being also completely glazed with 
water. It was, therefore, the under surface of the Musa leaves that transpired ; 
bat there was not the slightest proof that the upper surface of the vine leaves 
emitted any watery vapour, for not a particle of moisture could be discerned upon 
the under surfaces of the Musa. Transpiration, therefore, cannot be doubted ; and 
as pores are found, particularly on the lower surface of the leaves of trees and 
shrubs, and commonly upon both surfaces of herbaceous vegetables, it is reasonable 
to infer that their office is to expel water in the state of vapour, with some carbonic 
acid. 
"We do not here refer in any great degree io functions. Our object being the 
consideration of structure, we shall conclude this concise notice by a condensed 
analysis of the known components of leaves, upon the authority of botanical 
