This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
A few words on the composition of the permanent fabric of plants and the principal phenomena of plant-life may serve to show the importance of exercising the utmost care and forethought in all cultural operations.
Vegetable organisms consist of every intermediate gradation between a single cell without any visible reproductive organs, up to very complex combinations and modifications of tissue and elaborate organs of reproduction in the higher stages of development. We purpose limiting our remarks to the growth, composition, and functions of the nutritive organs, or root, stem, and leaves. All plants coming within our province are built up of an infinity of cells, forming two principal kinds of tissue, namely, vascular or woody tissue, and cellular or herbaeeous tissue. The cells themselves are composed of carbon, oxygen, and hydrogen, and their contents of the same elements, with the addition of nitrogen. With these essential elements several others are associated in different' plants. The commoner ones are phosphorus, sulphur, silex, potash, soda, and lime. The chemical compounds of organic origin are ternary, quaternary, or even more complicated; whereas inorganic compounds generally are binary. Sugar and starch may be mentioned as the most familiar vegetable compounds. Amongst vegetable acids, citric, malic, and oxalic are the commonest. Quinine, cinchonine, and morphine are valuable alkaloid drugs.