CLASSES AND NATURAL ORDERS. 35 



These are called net-veined leaves. As a general rule 

 plants with these net- veined leaves belong to one of the 

 two great classes of flowering plants (cf. Figs. I, 22, 27). 

 But now pick a leaf of the wild hyacinth or 

 snowdrop, or, which you are sure to find, a blade, 

 i.e., a leaf of grass. In this leaf you see that the 

 veins run more evenly side, by side, and though you 

 may find cross veins in leaves of this kind, yet they 

 never make an irregular branching network, (cf. 

 Fig. 169). Leaves of this kind are called straight- 

 veined. As a general rule plants with these straight- 

 veined leaves belong to the other of the two great 

 classes of flowering plants. There are a few 

 exceptions to this general rule, but until you learn 

 more about the other differences between the two 

 classes, and about their proper names, you can think 

 of them as the " net-veined " and " straight-veined " 

 classes. 



These two classes are then divided again until you 

 have the flowering plants arranged in about one 

 hundred divisions, which are called natural orders. 

 You will learn afterwards about the way in which 

 botanists arrange these " natural orders " under divi- 

 sions, and the " divisions " under the two classes. 



It is the arrangement of plants in their natural 

 orders that I want you to remember. Some of these 

 natural orders are very easy to learn about. I will 

 tell you about a few of them in my .next chapter. 

 But as they are known from one another chiefly by 



