138 GENERAL CONSIDERATIONS. [BOOK n. 



of increase. Of these little stunted branches, called spurs, 

 the terminal bud acquires a swollen appearance, and at length, 

 instead of giving birth to a new shoot, produces from its 

 bosom a cluster of twigs in the form of pedicels, each 

 terminated by a bud, the leaves of which are modified for the 

 purposes of reproduction, grow firmly to each other, assume 

 peculiar forms and colours, and form a flower, which had 

 been enwrapped and protected from injury during the previous 

 winter by several layers of imperfect leaves, now brought 

 forth as bracts. Sap is impelled into the calyx through the 

 pedicel by gentle degrees, is taken up by it, and exposed by 

 the surface of its tube and segments to air and light; but, 

 having very imperfect means of returning, all that cannot 

 be consumed by the calyx is forced onwards into the circula- 

 tion of the petals, stamens, and pistil. The petals unfold 

 themselves of a dazzling white tinged with pink, and expose 

 the stamens ; at the same time the disc changes into a sac- 

 charine substance, which is supposed to nourish the stamens 

 and pistil, and give them energy to perform their functions. 



At a fitting time, the stigmatic surface of the pistil being 

 ready to receive the pollen, the latter is cast upon it from 

 the anthers, which have remained near for that particular 

 purpose. When the pollen touches the stigma, the grains 

 adhere by means of its viscid surface, emitting a delicate 

 membranous tube, which pierces into the stigmatic tissue, 

 lengthens there, and conveys the matter contained in the 

 pollen towards the ovules, which the tube finally enters by 

 means of their foramina. 



This has no sooner occurred than the petals and stamens 

 fade and fall away, their ephemeral but important functions 

 being accomplished. The sap which is afterwards impelled 

 through the peduncle can only be disposed of to the calyx and 

 ovary, where it lodges : these two swell and form a young 

 fruit, which continues to grow as long as any new matter of 

 growth is supplied from the parent plant. At this time the 

 surface of the fruit performs the functions of leaves in expos- 

 ing the juice to light and air ; at a subsequent period it ceases 

 to decompose carbonic acid, gains oxygen, loses its green 

 colour, assumes the rich ruddy glow of maturity ; and the 



