94: METAMORPHOSIS OF ORGANS OF PLANTS. 



herbs decompose, and restore to the earth the elements which they had drawn 

 from its bosom. The earth, stripped of its boauty, seems sinking into old age ; — 

 Dut, although the processes of nature may have been unseen and unmarked by man, 

 innumerable germs have been formed, which wait but the favorable warmth to 

 decorate with new brilliancy this terrestrial scene. So fruitful is nature, that a 

 surface a thousand times more extended than that of our globe, would not be suf- 

 ficient for the vegetables which the seeds of one single year Avould produce, if all 

 should be developed ; but great quantities are eaten by men and animals, or left 

 to perish in unfavorable situations. Some are carried into the clefts of rocks, or 

 buried beneath the ruins of vegetables ; here, protected from the cold, they remain 

 inactive during the winter season, and germinate as soon as the early warmth of 

 spring is felt. Then the pious Botanist, beholding the vegetable species with wliich 

 the earth begins to be clothed, and seeing successively all the types or representa- 

 tions of past generations of plants, admires the power of the Author of nature, and 

 the immutabiiity of his laws. 



LECTUEE XYII. 



THEORY OF THE META:SI0RPH0SIS OF THE ORGANS OF PLANTS. 



104. We will take a general view of the groivth of plants^ 

 with the transforinatioii or inetamorphosis of the vegetable or- 

 gans climng the progress of development, from germination to 

 decay. • A seed may be considered as an organized^ living jplant. 

 "We have seen, that by the application of warmth, moisture, 

 and oxygen, its life becomes active ; it begins to develop parts 

 that before lay folded up, and concealed from observation. 

 Botanists of the present age have been much occupied in tra- 

 cing the germination of the seed, and the develojyinent and 

 tra/risforraation^ or inetainorjyliosis^ of the different organs of the 

 plant; it is found that these are but modified forms of the 

 various tissues from which they are elaborated. 

 • 105. The development of the organs of plants appears under 

 three forms : normal^ ohnorinal^ and accidental. The normal 

 process is exhibited in the progressive and regular development 

 of organs, according to established laws. The ^hiormal pro- 

 cess is when there is a failure to produce regular results, either 

 from irregular action, or a want of energy in the vital functions 

 of the plant. The accidental process is when irregularity is 

 produced by external causes, as the puncture of insects, extcr 

 nal injuries, &c. 



106. In the normal process, there is a regular progression 

 commencing with the seminal leaves, and going on through the 

 whole existence of the plant, developing various organs by 

 successive stages, to the final production of the flowers and 

 fruit. In annual plants the progress is rapid from the germi- 



Conclading remarks. — 104. The organs of the plant are modified forms of tissues. — 105. Tiiree forms 

 of development of organs. — 106. Normal process. 



