These facts have been offered, simple as they are, as striking examples of chemical and structural opposition.
The fungi include very simple organisms, as well as others of tolerably high development, of most varied form, from the simple bacillus and yeast to the truffle, lichens, and mushrooms.
The cell membrane of this class contains no pure cellulose, but a modification called fungus cellulose. The membrane also contains an amyloid substance, amylomycin.[8] Many of the chemical constituents found in the entire class are given in Die Pflanzenstoffe.[9]
Under the Schizomycetes to which the Micrococcus and Bacterium[10] belong are found minute organisms differing much in form and in the coloring[11] matters they produce, as that causing the red color of mouldy bread.
The class of lichens[12] contains a number of different coloring substances, whose chemical composition has been examined. These substances are found separately in individuals differing in form. In the Polyporus[13] an acid has been found peculiar to it, as in many plants special compounds are found. In the agariceæ the different kinds of vellum distinguish between species, and the color of the conidia is also of differential importance. In all cases of distinct characteristic habits of reproduction and form, one or more different chemical compounds is found.
In the next group of the musiceæ, or mosses, is an absence of some chemical compounds that were characteristic of the classes just described. Many of the albuminous substances are present. Starch[14] is found often in large quantities, and also oily fats, which are contained in the oil bodies of the liverworts; wax,[15] organic acids, including aconitic acid, and tannin, which is found for the first time at this evolutionary stage of the plant kingdom.
The vascular cryptogams are especially characterized by their mineral composition.[16] The ash is extraordinarily rich in silicic acid and alumina.
| Equisetum [17] | silicic acid | 60 | per cent. |
| Aspidium | " | 13 | " |
| Asplenium | " | 35 | " |
| Osmunda | " | 53 | " |
| Lycopodium [18] | " | 14 | " |
| " | alumina | 26 to 27 | " |
| " | manganese | 2 to 2.5 | " |
These various plants contain acids and compounds peculiar to themselves.
As we ascend in the plant scale, we reach the phanerogams. These plants are characterized by the production of true seeds, and many chemical compounds not found in lower plants.