12 THE LIFE OF THE PLANT 



With the naked eye, or, better still, with the help of a 

 lens, a small germ plant, a young shoot, consisting of a 



tiny stem with leaves and rootlet, 

 is easily recognised (fig. i). This 

 shoot binds together the two 

 halves of the seed, which are 

 called the cotyledons. These, 

 though much larger than the 

 Fig. I. shoot itself, are nothing but two 



appendages of it. But what is the 

 nature of these cotyledons? Botanists say they are leaves. 

 Those colourless, round, fleshy bodies, which remain 

 underground are called leaves not without reason, as we 

 shall immediately see. We have only to pass from a 

 bean to its nearest relative — say the haricot — to find 

 cotyledons appearing above the soil and becoming green 

 like ordinary leaves (fig. 2). In the maple and the ash 

 the cotyledons are still more like a common leaf, and 

 the lime actually has small thin green leaves with well- 

 marked veins and crenate outlines. Therefore the 

 cotyledons of a bean, though they grow underground 

 and are far from reminding us of actual leaves by their 

 colouring or appearance, must be nevertheless regarded 

 as such. Following upon those first organs, so unlike 

 leaves, there appear, as the stem elongates, real leaves, 

 though not yet of the shape we are accustomed to 

 meet on a grown-up plant. Here is, for instance, a 

 young ash plant. Everybody knows the shape of its 

 leaf. Several pairs of leaflets are distributed on a 

 common stalk with one leaflet more at the top. In this 

 way a whole leaf consists of seven, nine, or more leaflets. 

 This is called a compound leaf. What, then, do we 

 notice here ? (fig. 3). The two fleshy, tongue-shaped 

 cotjdedons are followed by two toothed leaves with 

 prominent venation, which are simple, not compound, 

 leaves. If we look further up the stem we shall notice 

 other leaves composed of three leaflets, higher up 



