556. As much as possible, plants should be examined in the living state, or when freshly gathered. But dried specimens should be prepared for more leisurely examination and for comparison. To the working botanist good dried specimens are indispensable.
[557.] Botanical Specimens, to be complete, should have root or rootstock, stem, leaves, flowers, both open and in bud, and fruit. Sometimes these may all be obtained at one gathering; more commonly two or three gatherings at different times are requisite, especially for trees and shrubs.
[558.] In Herborizing, a good knife and a narrow and strong trowel are needed; but a very strong knife will serve instead of a trowel or small pick for digging out bulbs, tubers, and the like. To carry the specimens, either the tin box (vasculum) or a portfolio, or both are required. The tin box is best for the collection of specimens to be used fresh, as in the class-room; also for very thick or fleshy plants. The portfolio is indispensable for long expeditions, and is best for specimens which are to be preserved in the herbarium.
559. The Vasculum, or Botanical Collecting-box, is made of tin, in shape like a candle-box, only flatter, or the smaller sizes like an English sandwich-case; the lid opening for nearly the whole length of one side of the box. Any portable tin box of convenient size, and capable of holding specimens a foot or fifteen inches long, will answer the purpose. The box should shut close, so that the specimens may not wilt: then it will keep leafy branches and most flowers perfectly fresh for a day or two, especially if slightly moistened. They should not be wet.
560. The Portfolio is best made of two pieces of solid binder's-board, covered with enamel cloth, which also forms the back, and fastened by straps and buckles. It may be from a foot to twenty inches long, from nine to eleven or twelve inches wide. It should contain a needful quantity of smooth but strong and pliable paper (thin so-called Manilla paper is best), either fastened at the back as in a book, or loose in folded sheets when not very many specimens are required. As soon as gathered, the specimens should be separately laid between the leaves or in the folded sheets, and kept under moderate pressure in the closed portfolio.
561. Of small herbs, especially annuals, the whole plant, root and all, should be taken for a specimen. Of larger ones branches will suffice, with some leaves from near the root. Enough of the root or subterranean part of the plant should be collected to show whether it is an annual, a biennial, or a perennial. Thick roots, bulbs, tubers, or branches of specimens intended to be pressed should be thinned with a knife, or cut into slices. Keep the specimens within the length of fifteen or sixteen inches, by folding, or when that cannot be done, by cutting into lengths.
[562.] For Drying Specimens a good supply of soft and unsized paper is wanted; and some convenient means of applying considerable pressure. To make good dried botanical specimens, dry them as rapidly as possible between many thicknesses of sun-dried paper to absorb their moisture, under as much pressure as can be given without crushing the more delicate parts. This pressure may be had by a botanical press, of which various forms have been contrived; or by weights placed upon a board,—from forty to eighty or a hundred pounds, according to the quantity of specimens drying at the time. For use while travelling, a good portable press may be made of thick binders' boards for the sides, and the pressure may be applied by strong straps with buckles. Still better, on some accounts, are portable presses made of wire network, which allow the dampness to escape by evaporation between the meshes. For herborization in a small way, a light wire-press may be taken into the field and made to serve also as a portfolio.
563. It is well to have two kinds of paper, namely, driers of bibulous paper, stitched into pads (or the pads may be of thick carpet-paper, cut to size) and thin smooth paper, folded once; the specimens to be laid into the fold, either when gathered or on returning from the excursion. These sheets are to hold the specimens until they are quite dry. Every day, or at first even twice a day, the specimens, left undisturbed in their sheets, are to be shifted into fire-dried or sun-dried fresh driers, and the pressure renewed, while the moist sheets are spread out to dry, so as to take their turn again at the next shifting. This course must be continued until the specimens are no longer moist to the touch. Good and comely specimens are either made or spoiled within the first twenty-four or thirty-six hours. After that, when plenty of driers are used, it may not be necessary to change them so frequently.
564. Succulent plants, which long refuse to part with life and moisture, and Spruces and some other evergreens which are apt to cast off their leaves, may be plunged for a moment into boiling water, all but the flowers. Delicate flowers may be encased in thin tissue paper when put into the press. Thick parts, like the heads of Sunflowers and Thistles, may be cut in two or into slices.