114 PERICARP AND SEED. 



nature ; each of these is called an ovule* and their outer cover 

 ing, an ovary. These ovules, before the fertilization of the 

 germ by the pollen, are scarcely perceptible ; after this period, 

 and the fading of the corolla, the ovules increase in size, and 

 the embryo and other parts which constitute the seed become 

 manifest. The ovary enlarges with the growth of the ovules; 

 the use of this covering is not confined to the mere protection 

 of the seeds from injury, but it is furnished with glands, which 

 secrete such juices as are necessary for the growth and de- 

 velopement of the ovules. As the ovary becomes more inatun- 

 it takes the name ofpericarj). Pericarps in their growth be- 

 come either woody or pulpy ; the letter absorb oxygen ga- 

 throw off carbonic acid; saccharine juices are elaborated in 

 their cellular integument. In another stage, the pulpy sub- 

 stance passes through a slight fermentation, the organization 

 is affected, the juices sour, the pulp decomposes and putrefac- 

 tion ensues. Such is the change which you may see in the 

 orange, apple, &c. during their progress towards maturity and 

 decay. 



Pericarp and Seed. 



The germ being fertilized, the piirts of the flower which are 

 not necessary for the growth of the fruit, usually fade, and 

 either fall off, or wither away. The germ continues to enlarge 

 until it arrives at perfection. Every kind of fruitf you can see 

 lias been once but the germ of a flower. The size of fruit is 

 not usually proportioned to that of the vegetable which produ- 

 ced it. The pumpkin and the gourd grow upon slender her- 

 baceous plants, while the large oak produces but an acorn. 



Every pericarp is formed of a parenchymous substance ; this 

 substance is surrounded externally by a cuticle called the epi- 

 carp, internally by a membrane called the endocarp, and an in- 

 termediate part called the mesocarp. In a peach, for example. 

 the kernel is the seed ; the fleshy substance the pericarp; the 

 skin is the epicarp ; the pulpy cellular substance, which ab- 

 sorbs a great quantity of sap and constitutes the principal part 

 of the fruit, is the mesocarp; the shell, deprived of moisture 

 and nourishment by the absorbtion of the mesocarp, and thus 

 contracted in its fibres and rendered dry and tough, is the en- 

 docarp. 



* From ovum, an r,gg. 



t The term fruit, in common Inn'ru.'ure, is limited to pulpy fruits which arc- 

 proper for food ; but in a botanical sense, the fruit includes the seeds and peri- 

 carps of all vegetables. 



Ovules Ovary Use of the ovary Its name in a mature state Pulpy peri- 

 carps Germ Size of fruit not in proportion to the plant that produces it 

 Epicarp Endocarp Mesocarp. 



