224 COMPOUND ORGANS OF PLANTS. 



store of nutriment on which it may subsist during the early 

 stages of its development. 



When the plant approaches the close of its allotted period of 

 life, it is surprising with what care provision has been made 

 for the continuation of the'species, as if nature had determined 

 to secure it, if possible, an immortality of existence upon the 

 earth's surface. Hence not only the beautiful contrivances to 

 effect the removal of the seed to spots favorable for its germi- 

 nation, but also the immense quantity of seed which the dying 

 plant produces. On a specimen of the castor oil plant, which 

 the author cultivated in his garden, he counted ten clusters of 

 pericarps, or seed-vessels; each cluster produced upwards of 

 fifty pericarps, and each pericarp contained three seeds. The 

 total number of seeds produced by the plant was, therefore, 

 10x50x3=1500. Each of these seeds, be it remembered, 

 contained within its folds an incipient repetition of the parent 

 plant in the form of a young embryo. Supposing each seed to 

 germinate, and the plants to arrive at maturity, the product of 

 the next season would be 1500x1500=2,250,000 seeds ! In 

 other plants, the first crop of seeds is still greater. It has 

 been calculated that the sunflower produces 4000 and a single 

 thistle 24,000 seeds the first year; therefore the second 

 year's crop would amount to 16,000,000 of seeds in the former, 

 and 576,000,000 of seeds in the latter instance. How immense 

 the amount of vegetable life which may spring from a single 

 seed ! Happily for mankind, every vegetable embryo is not 

 destined to give rise to a future progeny. Millions of seeds, 

 or vegetable embryos, are called ' into existence, but their 

 incipient life is speedily destroyed by a variety of causes. 

 Were it not for the operation of these causes, by which the 

 species is kept within prescribed limits, such is the fecundity 



