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COLLECTING AND PRESERVING PLANTS. 725

of the year. It may be premised that for botanical purposes fronds destitute of fructification are worse than useless, unless they belong to species which produce distinct fertile and barren fronds, and in which the characters and appearance of these fronds materially differ. In such cases the two kinds of fronds should be collected and preserved together.

The period for collecting ferns for the herbarium is, therefore, manifestly that when the fructification has nearly attained to maturity, and it is always better to collect them on a dry day than on a very wet one. The collector should go out prepared for collecting ferns, if he desires that his herbarium should present a neat and respectable appearance when completed. Some recommend a vasculum, some a bag, and some a large book under the arm; but commend us to two 4-in. deal boards, about 11 in. by 17 in., with a strap and buckle for each end, and twenty sheets of good bibulous paper, cut to the same size, and placed between them. Having selected a good frond or two for preservation, taking care not to break the stipe or stalk, but to separate it from the rhizome or root-stock, bend back the stipe just below the lowest leaflets of the frond, breaking the woody portion, but not dividing it from the rest of the frond, and lay it carefully between a sheet of your bibulous paper, and secure it with the spare paper between your boards; then proceed in search of more. Fronds which with their stalks are not too long for the paper should be laid in without bending.

In selecting fronds for preservation, it is not the largest that are required, but it is rather advisable to collect such specimens as will lie comfortably between the papers without bending than to aim at procuring fine specimens, which may only prove to be a nuisance. A perfect frond of 9 in. in length is better than a folded or otherwise mutilated one of 19 in. In selecting fronds, the fruit should not be too ripe, or instead of spores you will only find empty cases, not to mention the rusty dust that will continually tint your papers. It is better that the spores should be scarcely matured. Then, again, it should be noticed whether the frond is eaten by insects, broken, or in any other way imperfect. Such specimens are to be avoided if others can be obtained. Finally, the specimens selected should be well grown, and not distorted, unsymmetrical, or exhibit a tendency to sporting, or departure from the general type of the neighbouring fronds.

Having collected what specimens are required and conveyed them home, the next process consists of drying them for the herbarium. This is accomplished by removing them from the papers in which they have been collected and transferring them to fresh paper. Some persons are content with a stout unsized paper, such as employed by grocers for wrapping sugar, others will proceed to blotting-paper, whilst the majority will admit that Bentall's botanical paper is decidedly the best. The ferns should be transferred to a sheet of drying paper; two or three thicknesses, or even four or five, may be placed upon it, and then another specimen, and thus ad libitum. When all are in this manner transferred, the pile should be placed in a press, or with a stout board above and below, loaded on the top with some heavy weights- stones, bricks, old books, or anything applicable for the purpose. Twenty-four hours at the least, and forty-eight at the most, they should remain unmoved. At the expiration of this period each specimen should be transferred to a dry sheet of paper, with three or four thicknesses of dry paper between each specimen, and again put under pressure for the same period. The damp paper from which the specimens are taken should be at once dried in the sun or before the fire. It

is always advisable to change the sheet for each variety. The specimens should be laid on the paper with the under or fructifying surface uppermost, and the barren side of the frond applied to the paper. Small strips of gummed paper, about 1 in. in length, and not more than in. in width, should be laid across the principal and secondary ribs or branches of the frond, and each end fastened down to the sheet of paper; other pieces may, in like manner, be placed across the tips of the fronds, or wherever else appears to be necessary to secure the specimen to the paper. It may be suggested that too many such slips disfigure the specimen, and if there are not sufficient it cannot be retained in its place. Experience must be the best teacher. Some object to fastening the specimens to paper at all, others recommend gluing them down by the whole surface. Both these plans appear to us to be equally objectionable. If the specimens are loose, they are not only in danger of being broken or damaged, but of being misplaced and dissevered from the label which belongs to them. If wholly glued down, they cannot under many circumstances be removed from the paper, either to be transferred to other paper or for closer examination or comparison.

Each specimen having been mounted, the label which accompanies it should be fastened down beside it. This may be pasted. Finally, its generic and specific name should be written legibly at the lower right-hand corner. All the specimens belonging to one genus should then be collected together and placed between the folds of a sheet of paper, in. wider and longer when folded than the half-sheets upon which the specimens are mounted. These ,66 genera covers" may be of the same paper, or a smooth brown paper may be employed for the purpose. On the outside of the genera covers, at the lower left-hand corner, the name of the genus should be written in a good bold hand. The whole may be transferred to a deal box, the front of which is movable as well as the lid, being hinged to the bottom, so as to fall down and lie flat on the table. The lid may be so contrived as to hold the front in its place when closed. A deal box, 9 in. deep, 13 in. wide, and 20 in. long will hold a good collection, and if this ever should prove too small for the number of specimens obtained, a second box of the same dimensions will remedy the evil.

If it is considered desirable, a little camphor may be kept with the specimens, but the best preservative will be to look them all over, and thus allow the air to have access to them, once in every six months. With such precautions a collection may be preserved uninjured for years, provided always that it is kept in a dry place-not moderately, but thoroughly dry- or "mould" may injure irremediably what insects have spared.

Á neat little collection of ferns, of smaller pretentions, and less clains to be regarded in a scientific light, may be arranged in a kind of album or scrapbook, with "guards" introduced by the binder sufficient to compensate for the extra thickness caused by the insertion of the specimens. A tinted paper is often used in the manufacture of these books, which good taste may transform into a very interesting volume for the drawing-room table.

In collecting flowering plants it is essential that the plants should be collected when in flower, and, if possible, specimens in fruit should be collected and dried therewith. This will seldom be possible, but a later visit to the same spot may furnish fruiting specimens, which may be dried and placed with the flowering portion. Wherever the plant is small, or of moderate size, the whole of it, including the root, should be gathered, as this will make the specimens more valuable for reference and comparison, and give a better idea

of the plant. If the seeds are being shed, they should be collected and placed in a small envelope, which may be fastened on the sheet beside the plant when it is mounted for the herbarium. Stems which are too thick to lie flat, especially such as are woody, should be pared down at the back with a sharp knife, care being taken not to interfere with the front or exposed portion of the specimen.

CAUTION.--Never omit to place a label with every specimen, stating where it was found, and the date of the month and year in which it was collected. A good collection in all other points is almost valueless if this caution is not regarded.

Never put dried plants away, or enclose them in a box, until thoroughly dry, or they will become mouldy. Take care to keep them, when dried, in a dry place.

FERNS.

Ferns are not flowering plants, but they belong to a class in the vegetable kingdom distinct from exogens and endogens, in which the flowers are concealed, hence called "cryptogamia." We cannot say that they have no reproductive organs, although they are destitute of true flowers. Some persons call the cryptogamia "flowerless plants," including ferns, mosses, liverworts, lichens, fungi, and algæ under that name. It is to the ferns only that we desire to direct attention, and for this our remarks on the flowering plants will have prepared us. As the dicotyledonous plants have leaves possessing a network of veins, or reticulated venation, and the monocotyledonous plants a parallel venation, so ferns have veins which fork or divide in a regular manner into two parts like the prongs of a fork, and are said to have a furcate venation. Amongst foreign ferns this character is not so universal as in English species. There is another peculiarity in ferns which deserves to be remembered: when the leaves of a fern first appear above the soil, the upper part is usually coiled inwards like a watch-spring. (Fig. 1.) There are only two or three British species which do not fold in this manner. Moreover, the spores or seeds of ferns are borne on the under surface of the fronds, or, in a few instances, upon modified or metamorphosed fronds. The leaves of ferns are called fronds, because they combine the functions of stems with those of leaves.

The fronds of ferns are borne on a stalk, or “stipe," so that when we speak of the "stipe" of a fern, we mean thereby what would be called the "leafstalk" or petiole of a flowering plant. The bases of the stipes are attached to a rootstock or rhizome, and it is only in some foreign species, called "tree-ferns,” that an erect stem is produced.

It has been said above that the spores or seeds are borne on the under surface of the fronds, or occupy the whole surface of special and metamor phosed fertile fronds. These constitute the fruit or fructification, and appear as brown dots or lines or in confluent masses. These dots or lines, when scen by a lens, are found to consist of clusters or tufts of brown capsules, which are the thecæ or spore-cases. A single capsule is called a theca, but a cluster of them is termed a sorus. These clusters, or sori, are sometimes naked, but more commonly covered, especially in their carly stages, with a membrane

called an indusium or involucre. The presence or absence and form of this cover is of great importance in determining the genus and species to which a fern belongs. The variations in form and mode of attachment of the covers (indusa) will be alluded to by-and-bye. But to return to the thecæ or sporecases: each spore-case is somewhat globose, generally with a short stalk, and girt by an elastic ring. This ring may pass over the top of the spore-case (Fig. 2) in a vertical manner, or around it horizontally or obliquely (Fig. 3). In some ferns the spore-cases are destitute of a ring, but split down the centre into two valves (Fig. 4). The interior of the spore-cases are filled, when ripe, with the minute, brown, dust-like spores or seeds.

The ferns which we shall have to describe may in the first instance be divided into two primary groups, each containing several genera or groups of species. The distinguishing feature in this separation will be that in one group the thecæ, or spore-cases, are not surrounded by any annulus, or ring, which is much the smallest group, and includes but three genera, and which may be named exannulate, or "without a ring." The other and larger group has spore-cases always surrounded or girt by a ring, and this we shall call annulate, or "with a ring."

First of all, we will examine the small group which we have called

EXANNULATE (without a ring).—As already observed, only three genera constitute this group, of which two have the spore-cases borne on a special frond, and in the other the spore-cases are borne on the changed upper portion of an otherwise barren frond. In this group it will be observed that the thecæ or spore-cases are not borne in clusters on the backs or margins of unaltered, or but little altered, fronds, but are confined to a special portion of the plant, in which the whole surface so set apart is devoted to its spore-bearing office. The spore-cases are themselves globose, splitting across the centre into two valves, to permit the spores to escape. The principal features which may be employed to distinguish the three genera which compose this group are: the spore-cases are arranged on a simple and unbranched spike in adders' tongues (Ophioglossum); the spore-cases are arranged on a compound or branched spike in moonworts (Botrychium); the spore-cases are clustered upon the branched or metamorphosed upper portion of an otherwise barren frond in Osmund ferns (Osmunda). (Fig. 5.)

The general character of the spore-cases in this group are represented in Figs. 4 and 5.

The second and larger group contains all the genera which are

ANNULATE (with a ring).-That we may render the characters of this group plainer it will be necessary to resort to a further subdivision into minor groups.

If the spore-cases of all the species could be examined in succession, it would be observed that in a few of them the ring is oblique, whilst in the majority of them the ring is vertical. Thus we are enabled to remove the sub-group with oblique rings for future consideration, and for the present deal only with those genera in which the ring is vertical.

As the sub-group still reserved is a large one, it will be essential to find some other character which is common to a few of the genera and not present in the others. If we look at the clusters of spore-cases, which we have already observed are called sori, and which are arranged on the back or at the margins of the fronds, it will be observed that in some instances the tufts are quite naked, whilst in others they are covered with, or surrounded by, a membrane

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of variable form. This enables us to constitute two sections of our sub-group, in which

Section I.-The tufts of spore-cases are naked;

Section II.-The tufts of spore-cases are covered (indusiate).

The first section, with naked tufts, contains three genera, which may be distinguished by the following characters: the clusters are circular, and the margin of the frond is flat (not reflexed), in the polypodies (Polypodium). The clusters are at first circular, afterwards spreading one to the other and becoming confluent, the margin of the frond bent back (reflexed), in the parsley fern (Allosorus). The clusters are elongated or linear in the Jersey fern (Gymnogramma).

By attention to the above characters, it will be easy to refer any fern with naked sori, which is a native of Great Britain, to its proper genus.

The second section, with covered or indusiate tufts, or clusters of spore-cases, contains eleven genera, so that it will be necessary to separate those with true or evident coverings from those in which the covering is imperfect. If, with this limitation, we examine the seven genera in which the clusters are truly and manifestly covered, we shall find that in two of these the clusters are circular, in four of them the clusters are elongated, and in the seventh they form a continuous line down the frond. Thus we may state their characters: Clusters circular.-Covering kidney-shaped in the boss ferns (Lastrea). (Fig. 6.)-Covering circular in the shield ferns (Polystichum). (Fig. 7.) Clusters oblong or linear.-Covering oblong, kidney-shaped, and fringed at the outer margin, lady fern (Athyrium). (Fig. 8.)-Covering straight in spleenworts (Asplenium). (Fig. 9.)

Clusters in pairs.-Covering opening down the centre between the twin clusters in hart's tongue (Scolopendrium). (Fig. 10.)--Spore-cases concealed amongst brown chaffy scales in the scale fern (Ceterach).-Finally, the clusters of spore-cases form a continuous line along the back of the frond between the midrib and the margin, with a linear covering, in the hard fern (Blechnum). (Fig. 11.)

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