I.] BOTANY. 



the nitrogen in solution by the roots, from salts of 

 ammonia (or nitrates). Most plants contain moreover 

 small quantities of one or more mineral substances, 

 also absorbed in solution by the roots. 



The green colour which prevails amongst plants 

 depends on the presence of a peculiar matter (Chloro- 

 phyll) within the cells, especially those near the surface 

 of the plant. This matter is coloured green only by 

 the action of light, consequently plants grown in quite 

 dark places are never green, nor are those parts of them 

 which are not exposed to the light (such as the roots). 

 The lustrous hue and glossy appearance of most leaves 

 is due to the fact of the coloured matter not being 

 superficial, but inclosed in cells whose sides are 

 usually as transparent as glass, and whose surface 

 reflects the light. 



The Primary Divisions of Plants. Plants 

 do not present a disorderly mass of living things, 

 having no degrees of relationship one with another, 

 like children's letters or numerals emptied out of 

 a box ; nor are they related to one another equally, 

 differing in similar degrees, as one does from two, 

 two from three, &c. ; but they fall into groups variously 

 related to one another, some like brothers, others like 

 cousins, and so forth ; whence arises the classification 

 of the vegetable kingdom into sub-kingdoms, classes, 

 orders, genera, and species. 



There are two primary groups, or Sub-kingdoms of 

 plants; the Flowering and the Flowerless, which 

 differ very much indeed ; the Flowering having, 

 amongst other characters, usually very conspicuous 

 structures commonly known as flowers, which pio- 

 duce seeds ; and these seeds invariably contain an 



