Lichens (Vol. 16, p. 578), compound dual organisms, part algae and part fungus, interesting because the dual organism enables the plant to live where neither of its compounds could live alone. Iceland moss, valuable both for its nutritive and medicinal qualities, comes under this division.
Fungi (Vol. 11, p. 333), an enormous class, comprising, according to Saccardo, 32,000 different species.
Bacteria (see Bacteriology, Vol. 3, p. 156), minute organisms, also known as microbes, bacilli, etc., technically called Schizomycetes.
Insectivorous Plants (Vol. 14, p. 644), more correctly termed Carnivorous, belong to a number of distinct natural orders, but agree in the extraordinary habit of adding to the supplies of nitrogenous material offered them by the soil and atmosphere by the capture and consumption of insects and other small animals.
These are the main divisions, and from the articles describing them the student will acquire a sound knowledge of the characteristics which distinguish each. As a matter of fact, interest in botany as a subject is first inspired by the particular rather than the general—that is to say, the love of individual flowers leads to the study of their habits and life history, thence to a comparison which leads to the recognition of similar characteristics in plants having apparently widely different functions, so that the following section of the subject, touching the natural history of plants, though really placed last in a logical course of reading in botany, will contain much that is already known to the student who wishes to pursue the subject systematically.
Natural History
In the Britannica from the various articles concerning the natural history of individual plants it is easy to trace back to what family and main division each plant belongs. To the student beginning the subject it will be most suggestive to look up the accounts of the plants which are cultivated in his garden, or which he can find near his home, and find out the family relationship between subjects which appear to differ very widely both in habits and characteristics. From the outline given above in the paragraph devoted to systematic botany an indication will be given him of the surprises which are in store for him as he pursues his investigation. He would not at first suspect, for example, that asparagus and hyacinths were cousins, that roses, apples, and blackthorn are closely related, or that chrysanthemums and artichokes have any connection with one another, let alone cabbage and wallflowers. An excellent scheme to arouse the interest of the young student would therefore be to encourage him to pick out from the list below the names of plants with which he is familiar and of which he can get specimens, and thence work backward until the meanings of the main divisions of the vegetable kingdom are clear to him.
In the natural history section of the following list will be found in alphabetical order the plants which have separate articles in the Britannica. Many plants besides these are of course described. They will be found in the Index, where the volume and page on which a description will be found are given.
CLASSIFIED LIST OF ARTICLES IN THE BRITANNICA ON BOTANY
(For biographies of botanists, see the end of the chapter on Biology)