When I think of the difficulties I experienced at the outset of my study of marine botany, especially in the collecting and drying of seaweeds, I feel strongly inclined to urge all beginners to obtain some information concerning Marine Algæ before they go to the shore to collect for themselves. A very few hours of study with an experienced algologist, or even a perusal of some illustrated work on British algæ, will save much trouble and materially assist the unpractised eye in selecting specimens for the herbarium. I may here mention as highly useful to incipient algologists Dr. Landsborough's 'British Seaweeds' and Professor Harvey's 'Manual,' either of which may be obtained for a few shillings; but if my readers are resident in London, I advise them to pay a few visits to the Library of the British Museum, and there inspect Dr. Harvey's 'Phycologia Britannica.' In this magnificent work they will find coloured figures of nearly every British seaweed, with drawings from magnified portions, and various structural details of the highest value to students; and I once more impress on all collectors the importance of some degree of book-learning ere they sally forth, bag or vasculum in hand, to cull the lovely "flowers of the ocean," or gather what best may please them from the rejectamenta on the shore.
If the collector wishes to learn, not merely the names of plants, but to distinguish species, he will do well to provide himself with a copy of Harvey's little volume the 'Synopsis of British Seaweeds,' and a Stanhope or Coddington lens, by means of which he can examine portions of delicate plants as he finds them, and compare them with the descriptions given in the 'Synopsis'; in this way, if he have any success during his excursions, he will quickly become familiar with most of the plants which are cast ashore or grow within tide-marks.
Time will not admit of, neither is space at present available for, a single line beyond what may be practically serviceable to my youthful readers; therefore I will hasten to describe the course of action in seaweed-collecting as I have practised it for many years. At once, then, to the shore, but not to the sandy shore, for only useless decayed rubbish, or here and there some straggling plants of Zostera marina, or grass-wrack, will be met with there. The collector must away to the rocks, and search carefully every pool he meets with, from a little distance below high-water mark, and so on down to the water's edge, always remembering that it is better to collect while the tide is receding than as it is coming in.
Presuming that few persons will think of collecting seaweeds much earlier than the month of May, let me observe that most of the accessible species of olive and green plants which grow on rocky shores and in tide-pools, will be found from May to June in pretty fair condition, but very few red plants, except those which grow on the shady sides of rock-pools, or under the shelter of the larger olive weeds, will be met with until a considerable space is laid bare by the receding water at the low spring tides, about a day or two before and after the full moon.
As nearly all the rare red weeds grow in deep water, they are seldom taken in any degree of perfection unless they are dredged; but in the summer months, say from June to the end of August, many fine plants are occasionally thrown up from deep water, and others are found growing on the stems of the great oar-weeds, portions of which are cast ashore, beautifully fringed with one or more species of Delesseria and other rare Rhodosperms—in fact, during the rising tide, diligent collectors may secure many a lovely deep-water plant as it comes floating in, but which, if allowed to remain long exposed to the action of sunlight, will fade in colour and decompose before it can be mounted. This is especially the case with all the soft gelatinous red plants, such as the Callithamnia, and all the Gloiocladiæ, as well as a few of the softer olive weeds; and here I may observe that there is one genus of beautiful olive plants, the Sporochnaceæ, which must on no account be put into the vasculum with any of the delicate red plants, for they not only very rapidly decompose, but injure almost all others with which they are placed in contact. The species are not numerous, and they may be easily recognized, after having been previously studied from the coloured figures either in Harvey's 'Phycologia,' or in Bradbury and Evans's 'Nature-printed Seaweeds.' It is also a curious fact respecting this genus, that while they are all of a beautiful olive tint in the growing state, they invariably change to a fine verdigris-green in drying; and indeed this is very generally the case with the filamentous olive weeds, the Fuci, or common rock-weeds, as constantly turning quite black after mounting: whence the term, that of "Melanosperm," which is given to the subdivision to which all the olive weeds belong.
As there are so few seaweeds which have generally known common names, I shall make no apology for using the names by which they are known to science, presuming that all intending collectors will, as I have already suggested, gain some knowledge of Terminology ere they go out "seaweeding."
Beginners should be cautioned against the very natural error of bringing home too many plants at a time; they must be moderate in their gatherings, or be content to risk the loss of some choice specimens, which will decompose unless they are attended to before night. The first thing to be done upon arriving at home, is to empty the collecting-bag into a white basin of sea-water, and to select the best and cleanest plants as soon as possible, giving each a good swill before placing it in another vessel of clean water, and getting rid of rejected plants at once, so that the basin first used will be available for rewashing the weeds before they are severally placed in the mounting dish. When a day is fixed on for seaweeding, the collector should order a large bucket of clean sea-water, which, after being left to settle, should be strained through a towel, so as to be as free as possible from sand and dirt. Two or three large pie-dishes will be necessary, the deeper the better, and white, if such can be obtained. Place these on a separate table with towels under them, and reserve a table specially for the mounting dish and the parcels of papers, calicoes, and blotting-papers. The large white bath used in photography is very well adapted for mounting seaweeds; the lip at one corner is convenient for pouring off soiled water, and its form—that of an oblong—is most suitable for receiving the papers on which the plants are to be mounted. Beside this vessel should be placed the following implements—a porcupine quill, two camel-hair pencils (one small, the other large and flat), a pair of strong brass forceps, a penknife, a pair of scissors, a small sponge, an ivory paper-knife, and two thin plates of perforated zinc somewhat less in length and breadth than the inside of the mounting dish.
Smooth drawing paper, or fine white cartridge paper, is generally employed for mounting. The operator should be provided with three different sizes of paper, and these should have each a piece of very fine calico and four pieces of blotting-paper to correspond. The process of mounting one of the filamentous or branching species is as follows:—The specimen being cleaned and placed in the mounting dish, a piece of paper of suitable size is laid on one of the perforated zinc plates, and both are then slipped quickly under the floating weed. The root or base of the specimen is then pressed down on the paper with a finger of the left hand, while the right hand is employing the forceps or porcupine quill in arranging the plant in as natural a position as possible, ere the zinc plate is gently and gradually raised at the top or bottom, as may be necessary, to ensure a perfect display of every portion of the plant; but if, upon drawing it out of the water, it should present an unsightly appearance from too thick an overlapping of the branches, the whole must be reimmersed, and a little pruning of superfluous portions may be employed with advantage to the specimen and satisfaction to the operator. Care should be taken that the water be drained off the paper as completely as possible before the calico is laid over the plant, and this is accomplished by raising the paper containing the plant as it still lies on the zinc plate, and transferring it to a thin board placed in an inclined position against one of the basins, and with the large camel-hair pencil paint off the water as it runs away from the specimen, and absorb what remains, when the paper is laid flat, with the sponge. Delicate species may be left to drain for a few minutes, while the operator is arranging other specimens. When the water is sufficiently drained off, the paper is then laid on the blotter, and the piece of calico is placed upon the plant—a sheet of blotter being laid upon the calico.
Care should be observed in subjecting plants to pressure, which, in the first instance, should be sufficient only to help the absorption of water. The first set of blotting-papers should be changed in half an hour after the whole batch of specimens have been placed in the press, and these must be thoroughly dried before they are used again. After the second or third change of blotters, the plants should remain under strong pressure for two or three days; but the pieces of calico must not be removed until it is pretty certain that the papers and plants are quite dry.