I desire now to call attention to chemical groups under the apetalous plants having simplicity of floral elements.

Cassuarina equisetifolia[20] possibly contains tannin, since it is used for curing hides.  The bark contains a dye.  It is said to resemble Equisetum[21] in appearance, and in this latter plant a yellow dye is found.

The Myrica[22] contains ethereal oil, wax, resin, balsam, in all parts of the plant.  The root contains in addition fats, tannin, and starch, also myricinic acid.

In the willow and poplar,[23] a crystalline, bitter substance, salicin or populin, is found.  This may be considered as the first appearance of a real glucoside, if tannin be excluded from the list.

The oak, walnut, beech, alder, and birch contain tannin in large quantities; in the case of the oak, ten to twelve per cent.  Oak galls yield as much as seventy per cent.[24]

The numerous genera of pine and fir trees are remarkable for ethereal oil, resin, and camphor.

The plane[25] trees contain caoutchouc and gum; peppers,[26] ethereal oils, alkaloids, piperin, white resin, and malic acid. Datisca cannabina[27] contains a coloring matter and another substance peculiar to itself, datiscin, a kind of starch, or allied to the glucosides.

Upon the same evolutionary plane among the monocotyledons, the dates and palms[28] contain in large quantities special starches, and this is in harmony with the principles of the theory.  Alkaloids and glucosides have not yet been discovered in them.

Other monocotyledonous groups with simplicity of floral elements, such as the typhaceae, contain large quantities of starch; in the case of Typha latifolia[29] 12.5 per cent., and 1.5 per cent. gum.  In the pollen of this same plant, 2.08 per cent. starch has been found.

Under the dicotyledonous groups, there are no plants with simplicity of floral elements.

Returning, now, to apetalous plants of multiplicity and simplification of floral elements, we find that the urticaceae[30] contain free formic acid; the hemp[31] contains alkaloids; the hop,[32] ethereal oil and resin; the rhubarb,[33] crysophonic acid; and the begonias,[34] chicarin and lapacho dyes.  The highest apetalous plants contain camphors and oils; the highest of the monocotyledons contain a mucilage and oils; and the highest dicotyledons contain oils and special acids.

The trees yielding common camphor and borneol are from genera of the lauraceae family; also sassafras camphor is from the same family.  Small quantities of stereoptenes are widely distributed through the plant kingdom.

The gramineae, or grasses, are especially characterized by the large quantities of sugar and silica they contain.  The ash of the rice hull, for example, contains ninety eight per cent. silica.

The ranunculaceae contain many plants which yield alkaloids, as Hydrastia canadensis, or Indian hemp, Helleborus, Delphinum, Aconitum, and the alkaloid berberine has been obtained from genera of this family.