24* The Ottawa Naturalist. 



from the first pair and resemble those of the maple as usually seen. 

 Later, a third joint shoots up from the summit of the second, bearing a 

 third pair of leaves, and so on until the plant likeness ot the seed be- 

 comes a fully developed tree. The three organs, root, stem, and leaves, 

 which exist in the embryo in a rudimentary state, are called the funda- 

 mental organs or organs of vegetation, because they have for their 

 object the development and nutrition of the plant ; while all the parts 

 which succeed the leaves, such as the flower and its organs, are only 

 modifications of them designed for a special purpose, and are called the 

 organs of reproduction, since on them depends the increase of the plant 

 in numbers, or the continuance of the species. 



Proceeding onward with his reading the student will obtain some 

 general knowledge of the various sorts and forms of these two sets of 

 organs, and afterward will get an insight into the life of plants, and the 

 mode in which they do the work of vegetation. He will discover that 

 all plants possessing leaf-green (Chlorophyll) as the pigment which gives 

 the green color to the leaves is called, possess also the power of assimil- 

 ation, that is of making starch and similar organic compounds out of 

 inorganic elements, such as water and carbonic acid ; which trans 

 formation, briefly speaking, is thus effected. The plant through its 

 roots, by the process known as osmose, takes in, dissolved in water, 

 various compounds containing carbon, oxygen, hydrogen, nitrogen and 

 other materials. The pressure exerted by the liquid as it comes into 

 the. roots, together' with the attraction exerted by a constant process of 

 -evaporation from the leaves, causes the " sap," which is the plant food, 

 to rise, and gives us what is known as the plant circulation. When, by 

 this osmotic action, the sap finally reaches the leaves, it. in conjunction 

 with carbonic acid derived from the air, is converted, in the chlorophyll 

 grains under the influence of sunlight, into organic materials, which 

 pass into a whitish granular liquid called protoplasm, and are used in 

 "growth." that is in the building ot new cells to form plant tissue. 

 \-Minilation takes- plate only in sunlight, but growth goes on most 

 rapidly at night. In the former process oxygen is set'free and given off 

 through the leaf-pores or stomata, but in the latter, air is taken in 

 through the "stomata, and,- as its oxygen is used up, carbonic acid gas is 



