18 NEW ZEALAND NATURE-STUDY BOOK 
How to distinguish Compound Leaves. A 
compound leaf consists of a number of separate leaflets 
attached to a common stalk. Why, it may be asked, do 
we not call it a branch, and speak of the leaflets as leaves ? 
A number of reasons may be given to show that a 
compound leaf is not a branch, but a single leaf. A 
knowledge of these, moreover, will enable us to determine 
whether a leaf is simple or compound. 
In the first place, if the leaf-stalk of a compound leaf 
were a branch, it would arise in the axil of a leaf—but 
this it does not do—on the contrary, it has a bud in 
its axil. Then, again, if the leaflets were true leaves, we 
would expect to find buds in their axils, but these do not 
occur in this position. Finally, a branch terminates, not 
in a leaf, but in a bud; hence, if we find a stalk bearing a 
terminal leafiet, we may conclude that the stalk with its 
leaflets is not a branch. An examination of a few compound 
leaves will make this absolutely clear to a class. 
Monocotyledons and Dicotyledons. Ifa Pea seed 
and a grain of Wheat be caused to germinate, the former 
we have seen will be found to possess two seed-leaves, and 
the latter only one. Experiments with a number of other 
seeds will show that in all cases germination results in the 
production of either one or two seed leaves. From this it 
will be seen that plants readily fall into two classes—those 
having one seed-leaf, such as Wheat, Maize, etc.; and those 
having two seed-leaves, like the Pea, Bean, Turnip, ete. 
The former are called Wisnoceniedon>) and the latter 
dicotyledons. | 
Further differences will easily be noticed. ¢.g., That the 
roots of monocotyledons consist of a number of independent 
fibres spreading out in all directions, and that their 
branches bear parallel-veined leaves; on the other hand, 
that a dicotyledonous plant sends down a single main root, 
