34 THE BOOK OF NATURE STUDY 



The bracts, ovary, and calyx bear short sticky glandular hairs, 

 and similar hairs are scattered on the outside of the corolla tube. 

 The corolla is the conspicuous part of the flower. It consists 

 of a long, gradually widening, tubular portion, which is split at 

 the wider free end into two lips. The lower lip is very narrow, 

 and is formed of one petal, while the broad upper lip has its margin 

 divided into four narrow lobes, showing that it is composed of four 

 petals. The five petals alternate in position with the sepals. 

 Projecting from the opening of the corolla tube are the five stamens 

 (st) and the style (sty). Each stamen has a long stalk, to the end 

 of which the anther is attached by its middle, so that it swings 

 freely. On carefully slitting up a corolla tube it will be seen 

 that the stamens are attached to the inner surface, alternating 

 in position with the petals. The style, which springs from the 

 summit of the inferior ovary, projects even farther forward than 

 the stamens ; it ends in a dilated, three-lobed stigma. On 

 cutting across the inferior ovary it will be found to have three 

 cavities, in each of which are several ovules. This fact, taken 

 together with the three-lobed stigma, shows that the pistil is 

 composed of three carpels. 



Having learnt by the dissection of a flower the parts of which 

 it is composed, the relative positions of these in flowers of various 

 ages must be clearly ascertained if we are to understand the way 

 in which pollination takes place. If an inflorescence is looked at 

 in the middle of the day, flowers in two stages will be readily dis- 

 tinguished by their colour. Some are paler and appear almost 

 white in comparison with others, the corolla of which has a full 

 yellow tint. The flower for some time after it opens has the 

 former appearance (Plate, Fig. 3). The two lips of the corolla 

 are not rolled far back ; the style ending in the stigma is bent down 

 parallel to the lower lip, and the stamens stand out in the opening 

 of the flower and are shedding their pollen. The flower is in the 

 early pollen-shedding stage. In the older yellow flowers (Fig. 4), 

 on the other hand, the stamens have shed their pollen, and are 

 bent downwards and the style has risen up and bears the stigma 

 full in front of the opening of the flower. The flower is now in 

 a purely pollen-receiving stage. The bud opens one evening, and 

 the flower is in the first stage; by the next evening, i.e. when new 



