TOO THE BOOK OF NATURE STUDY 



the foliage-leaves or the sepals in texture and colour. Each is 

 attached by a narrow base to the receptacle, and widens out 

 gradually from this to the rounded margin. Except for a region 

 of the upper surface close to the attachment where the colour 

 is paler, the petal has a bright yellow colour ; the surface is 

 dull below, but smooth and shining above. Everything about 

 the petals shows that they are of use in making the flower con- 

 spicuous. The reason for this we shall see later. 



If a petal be carefully pulled off and looked at from the inner 

 or upper side another feature of interest will be noticed. Close 

 to the base of the petal is a small yellow scale ; this is short, and 

 is almost as broad as the narrow part of the petal against which 

 it lies. The free edge of the scale can easily be raised with the 

 point of a knife, and a little recess or pocket will be found to 

 exist between the scale and the petal. In this pocket a sweet 

 sugary juice called nectar is formed and held, and the structure 

 secreting it is called the nectary. The use of the nectar will also 

 be seen shortly. 



The parts of the flower within the corolla are less leaf-like 

 than the petals and sepals, and require careful study with the 

 help of the pocket lens. Immediately above the petals on the 

 receptacle come a large number of stamens. They do not form 

 whorls, but are spirally arranged. Each stamen is composed 

 of a cylindrical stalk, bearing a widened, flattened portion ; 

 the stalk is called the filament, the upper part the anther. The 

 whole stamen has a more or less intense yellow colour. The 

 filament calls for no further description, except to say that it 

 continues directly into the middle portion of the anther, between 

 the two halves of which it can be traced as the connective. This 

 is most easily seen on the side of the anther turned towards the 

 centre of the flower, since the two halves or lobes of the anther 

 face outwards and conceal the continuation of the stalk on this 

 side. Each lobe of the anther contains two cavities called pollen- 

 sacs, within which the pollen is formed. When the stamen is 

 mature a longitudinal slit forms on either side of the anther, 

 opening the pollen-sacs, and the pollen is shed as a somewhat 

 adhesive, yellow, powdery mass. The formation of the pollen, 

 which consists of isolated cells, is the function of the stamen. 



