These collections contains:
1o Herbals or plants dried in leaves of paper;
2o Fruits and preserved seeds, either dry or in alcohol;
3o Pulpy flowers also preserved in liquor;
4o Portions of roots, trunks and samples of wood;
5o Different products of the vegetable kingdom, such as flax, starch, gums, resins, dyestuffs, substances employed in the medicine or the arts;
6o Samples relative to anatomy and vegetable physiology.
The care necessary to enrich these collections are generally less than those required for zoology.
Herbals and collections of fruits and flowers—Samples in buds, flowers and fruits of plants intended for herbals should be collected when the plant is small, and generally when it is of a size to be kept in a leaf of paper by folding. It should be taken with the root; when it is larger, it should be cut in pieces of 40 or 50 centimetres (16 to 18 inches). Or the great herbaceous plants, whose leaves vary often at different heights on the trunk, the base of the stalk with the leaves that support it should be preserved,—and branches with flowers and leaves. A layer of several leaves of brown paper is placed alternatively with a sample of a plant, or several, if they are small and can be spread on the paper without touching. Then a new layer of paper, then a new sample, and so on. When the packet has a certain thickness (2 to 3 decimetres at most) it should be pressed between two pieces of paste board by means of cords or girths and a buckle. The pressure should be moderate, enough to prevent the plants from wrinkling, but not enough to change their shapes, or crush their tissue by flattening them too much. The parcels, to dry well, should be placed on a dry board; or, better, hung up, so that the boards be in a vertical position. It is well to change several time the layers of paper; first, soon after the drying has commenced.
The drying of plants may be much quickened by dividing them into packets of 8 or 10 packets only, with very little paper between, and pressing them between two frames furnished with a wire grate tied up by strings; a layer of four or five leaves of paper should be placed on each side, immediately under the grate, to render the pressure more uniform and keep the plants from crisping; if these small packets are exposed to the sun or a current of air, the plants dry rapidly, often before the paper is changed that contains them; but unless there is a great number of these frames, it is impossible to dry but a small number of plants, and this process would be especially useful for those persons to whom the formation of an herbal is but an accessory occupation.