CHAPTER VII. 



BRACTS AND FLORAL LEAVES. 



MORPHOLOGY. 



We now come to the consideration of the remaining two kinds of 

 leaf, i.e., bracts and floral leaves. The latter make up the greater 

 part of the flower, which may be defined as a shoot specially 

 modified for carrying on the function of reproduction. Bracts 

 are leaves, usually much reduced, which occur near the flower. 

 It will be necessary, in order to understand the various parts 

 which make up a flower, to carefully examine a simple example. 

 It is usual to select a buttercup for this purpose. First, with a 

 sharp penknife or scalpel divide the flower into halves, in which 

 operation it is desirable to commence by splitting the flower- 

 stalk or peduncle. The cut thus made is then continued. If 

 this is done successfully, it will readily be seen (fig. 30) that the 

 continuation of the peduncle within the flower forms a conical 

 structure upon which are crowded numerous parts of different 

 shapes and sizes. This conical body, the floral receptacle or 

 torus, is in reality the stem part of the floral shoot, while the 

 structures situated upon it are the leaf part of the same. The 

 crowding is caused by non-development of internodes, a common 

 occurrence, as we have already seen, in the ordinary vegetative 

 shoot. Now, in another specimen, proceed to examine the various 

 kinds of floral leaf, beginning at the outside. First comes a 

 whorl of five small yellowish-green leaves, the sepals, collectively 

 forming the calyx. Then follows another whorl of five much 

 larger bright-yellow leaves, the petals, which make up the corolla 

 and alternate with the sepals. Now pull off the calyx and corolla, 

 and, before examining the more internal parts, carefully inspect 

 the glossy inner side of a petal. Close to its attached end will 

 found a minute scale covering a spot which excretes honey or 

 nectar, and is known as a honey gland or nectary. Within the 

 perianth ( = calyx + corolla) are a very large number of yellow 

 threads arranged spirally, though this is not easily made out. 

 The threads are stamens, and their collective name is androecium. 

 The thin stalk of a stamen is its, filament, and the thickened end 

 its anther, within which an immense number of minute pollen 



