PART I.

The kindred subjects of the collecting of plants and their arrangement in the herbarium have been treated of over and over again, and it might almost seem as though nothing further need be said upon the matter. But in spite of all that has been written, it cannot be said that anything like uniform excellence has been attained, either in the collecting or drying of specimens: on the contrary, much carelessness is still exhibited in both particulars, and the following remarks on the subject may therefore be useful to some, at any rate, among the readers of 'Science Gossip.' It has been found impossible to treat both points adequately in one paper, so, on the present occasion, we shall devote ourselves to collecting, leaving the arrangement and matters connected therewith for another occasion.

The great aim to be kept in view in collecting is to obtain as perfect and comprehensive a specimen as possible; that is, one showing every part of the plant--root, leaves, flowers, and fruit. It is not always practicable to show all these upon one specimen, and in such cases such a number must be selected as will carry out this plan. The wretched scraps with which some collectors content themselves are not only useless to their owners, but annoyances to everyone who has to do with them, or who is requested to pronounce an opinion upon them. Anyone who has had anything to do with naming plants for 'Science Gossip' or any other journal, which in this manner supplies information to its subscribers, will be able to testify to the large number of persons who do not scruple to send for determination single leaves, or a terminal shoot of a flowering plant, or a pinnule of a fern without fruit; a proceeding which is unfair to those to whom they are submitted, inasmuch as they either have to risk their reputation for accuracy, or to appear uncourteous by refusing to have anything to do with such specimens.

To begin at the beginning, How rarely do we find the embryo of any species represented in a collection of dried plants? It ought to be there, not only as essential to the complete presentment of the history of the species, but as in certain cases indicating relationships which are not apparent when the plant is more advanced. Those who have not observed them would be surprised to find how much variety of form exists in the cotyledons alone, from the fleshy cotyledons of many of the Leguminosæ, the horse-chestnut, &c., to the foliaceous ones, or seed-leaves, of other plants. Among the latter may be noted and compared the lobed or palmate cotyledons of the lime (Fig. 32); the glossy dark green, somewhat kidney-shaped ones of the beech (Fig. 33); and the pinnatifid ones of the common garden cress (_Lepidium sativum_); the obcordate ones of the mustard or radish; the long, narrow, thin ones of the sycamore (Fig. 34); the sinuous or corrugated and bilobed ones of the walnut, and many more which will occur to the observant reader, or which may be collected by anyone who will take the trouble to watch the germination of plants. And by making such collections, unexpected discoveries may arise, which will yet further confirm what has been said about the variety in form and structure even in these beginnings of growth. Plants which are, on account of their general affinities, reckoned among the dicotyledons, may be found on investigation to have but one cotyledon, as Dr. Dickson observed to be the case with two of our butterworts, _Pinguicula vulgaris_ and _P. grandiflora_, the third species, _P. lusitanica_, being dicotyledonous; or even to be acotyledonous, as is the case with the dodder (_Cuscuta_). In the latter-named genus, it is of importance to collect young specimens, as showing that the plant, although parasitic as soon as it comes in contact with a suitable foster-plant, is of independent origin. A search among young plants will no doubt lead to the discovery of some abnormalities, such as tricotyledonous embryos and other irregularities. Of some plants, such as the furze, the true leaves can only be found at an early stage of growth; in others, much variation may be noted in many points between the first leaves and the more perfect ones which succeed them; some, as the holly, at once developing leaves similar to those which are produced throughout the life of the plant, and others going through many modifications before the ultimate shape is attained, as in the ash, elder, ivy, maple, &c.

The roots or rhizomes also require to be much more fully represented and carefully collected than is usually the case. In every instance where the size of the plant does not prevent, the subterranean and subaqueous parts should be carefully procured and preserved.

Dr. Trimen has lately directed attention to the corm-like tubers of the water plantain (_Alisma_),[G] closely resembling those of the arrowhead (_Sagittaria_), which have been described and figured by Nolte, but "do not seem to have been observed, or at least properly understood, in this country. They are buds remaining dormant through the winter, and containing a store of nutriment, to be employed in the development of the new plant from the tuber in the next year." Similar bulbs are developed by the frogbit (_Hydrocharis_). In determining many grasses and rushes, it is of importance to ascertain whether the rhizome is creeping or cæspitose, and it is therefore essential to collect good specimens. In the case of such plants as the coral-wort (_Dentaria bulbifera_) and toothwort (_Lathræa squamaria_), the root-stocks are eminently characteristic. Of such parasites as the broomrapes (_Orobanche_), some care is requisite in obtaining specimens in which the connection between the parasite and its foster-plant may be preserved and shown. The absence or presence of tubers should also be noted, and if present, they must be represented.

[G] 'Journal of Botany,' 1871, p. 306.

Passing on to the leaves, we may note the importance of obtaining in every case the root-leaves of each species. These are often very different in form from the stem-leaves, as in such species as the harebell (_Campanula rotundifolia_), _Pimpinella saxifraga_, the earth-nut (_Bunium flexuosum_), and many more; in some instances, as in the Jersey bugloss (_Echium plantagineum_), they at once characterize the species. Still more important are these lower leaves in the case of water-plants: in the arrowhead (_Sagittaria_), for example, they are narrow, and resemble those of the bur-reed (_Sparganium_); and in the water plantain (_Alisma plantago_), the submerged leaves are equally different from those which rise out of the water. This difference is still more noticeable in the case of the aquatic _Ranunculi_, where a knowledge of the submerged leaves is essential to the discrimination of the various forms or species.

Where practicable, the whole plant should be collected for the herbarium; but when, from its size, this cannot be accomplished, leaves from the root, the centre of the main stem, and the lateral branches, should be taken. As to the stem itself, that must be represented: in the _Rubi_, indeed, it is essential. "To judge properly of a bramble from a preserved specimen," says Professor Babington, "we require a piece of the middle of the stem with more than one leaf; the base and tip of the stem are also desirable, likewise a piece of the old stem with the flowering shoot attached to it; the panicle with flowers, and the fruit. We likewise want to know the direction of the stem throughout, of the leaflets, and of the calyx; also the shape of the petals and the colour of the styles: a note of these should be made when the specimen is gathered."

Passing on to the flowers, we shall find it necessary to represent them in almost every stage, from the bud to the perfecting of the fruit. It is of course in most cases possible to select an example in such a state as to show upon the same plant buds, flowers, and fruits; but where this is not the case, each of these particulars must be supplemented by additional specimens. The turn which botanical investigation has recently taken towards the study of the phenomena connected with fertilization has given the collector another subject to which his attention may be profitably directed. It has been observed that in some plants the stamens are developed before the pistils; in others, the pistils are matured before the stamens; while in yet a third set, stamens and pistils are simultaneously perfected. These three groups of plants are termed respectively protandrous, protogynous, and cynacmic, and a very little observation will show that examples of each are sufficiently common.

Then in dioecious and monoecious plants, both male and female flowers must be collected, and in some cases, as in the willows, four specimens are necessary to the complete presentment of the species, showing respectively the male and female catkins, the leaves, and the fruit. Some plants produce two distinct forms of blossom, as is noticeable in the violets and the woodsorrel, one being conspicuous and usually barren, the other insignificant and often apetalous, but producing perfect fruit. The pollen will afford occupation to the microscopist: the researches of Mr. Gulliver and Mr. Charles Bailey have demonstrated that important distinguishing characters are in some instances furnished by it. While on this point it may be suggested that it is convenient in many cases to collect several specimens of the flowers alone, which, when dried, should be placed in a small envelope or capsule, and attached to the sheet on which the plant is represented. In the event of any examination which may be requisite after the plant is dried, these detached blossoms will be found very useful, and will prevent the necessity of damaging the specimen. In the case of such plants as shed their corollas very readily, as the speedwells, it is as well to put them in press as soon as collected; and the colour of many may be retained by the same means.

The fruits and seeds of plants are too generally neglected by amateur collectors, but are essential to the completeness of a specimen. It may be found practically convenient to keep these in a separate place, and detached from the plant; and in many cases of dried fruits it is advisable to sort them into their places without previous pressing. By this means the modes of dehiscence will readily be seen: pulpy and succulent fruits should be preserved in spirit. In such plants as the species of sea sandwort (_Lepigonum_), and some Chenopodia, important specific characters are drawn from the seed; as they are from the pods of _Melilotus_ and the fruits of _Agrimonia_. In collecting ferns, well-fruited fronds must be selected, as it is impossible to determine specimens without fructification. Grasses should be selected when in flower and fruit, but must not be allowed to attain too great an age before they are collected.

We have been speaking so far of the things to be collected, and space will not allow us to dilate at any length upon the apparatus necessary to that end. Nor indeed is this necessary; a good-sized vasculum, with one or two smaller boxes for the pocket, in which the more delicate plants may be preserved; a strong pocket-knife or small trowel, for procuring roots, and a hooked stick wherewith to fish out water-plants, or pull down branches, are the principal things required. To anyone residing for any length of time, or even only for a few days, in a district, a "London Catalogue" is an important acquisition, in which should be marked off all the species met with; by this means the flora of the neighbourhood is ascertained at a very slight expenditure of time and trouble. It is not advisable to collect too many plants at once, or to crowd the vasculum, unless under exceptional circumstances; nor should the desire to possess rare plants tend, as is too often the case, to the neglect and exclusion of commoner ones.

A careful and observant collector will frequently meet with forms which deviate more or less from the accepted type of a species. When these appear to offer any marked characters, they should be noted; and in all cases it is well to preserve any forms which, from external circumstances, have a different appearance from the normal state. The differences produced by soil and situation alone are very considerable; and though the essential characters are usually to be discerned, the interest and value of a herbarium are very much increased by a selection of examples showing the range of a species. _Campanula glomerata_ offers a good example of this. In damp meadows it is from one to two feet high, with a large spreading terminal head of blossoms, while on chalk downs it does not attain more than as many inches, with only one or two flowers; in this state it was described by Withering as a gentian, under the name of _Gentiana collina_; and the same author gives as _Campanula uniflora_ a one-flowered mountain state of the harebell (_C. rotundifolia_).

The collector will also do well to keep a look-out for deviations in structure, which are often of great interest. In short, nothing should be neglected which can tend to the perfect presentment of a species in the herbarium: its utility is commensurate with its completeness. The mere collector may be satisfied with scraps of a rare plant and the absence of commoner species; but the real worker will pride himself rather upon the possession of instructive examples, which may be of assistance to himself, as well as to all those who may consult them.

IX.

FLOWERING PLANTS AND FERNS.

By James Britten, F.L.S.