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 typhaceæ, 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 urticaceæ[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 lauraceæ family; also sassafras camphor is from the same family. Small quantities of stereoptenes are widely distributed through the plant kingdom.
The gramineæ, 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 ranunculaceæ 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.
The alkaloid[35] furnishing families belong, with few exceptions, to the dicotyledons. The colchiceæ, from which is obtained veratrine, form an exception among the monocotyledons. The alkaloids of the fungus have already been noted.
[36]Among the greater number of plant families, no alkaloids have been found. In the labiatæ none has been discovered, nor in the compositæ among the highest plants.