The value of this plant in polishing is, of course, due to the silicious substance in its stems, as was first, I believe, positively pointed out by Sir Hum-phrey Davy. The cells incrusted with this silex may be seen by the aid of a microscope, arranged with the most harmonious regularity in those longitudinal ridges, which give so peculiar and distinctive a cha-racter to the whole stem; and so accurately is every cell fitted to the others, that if the plant be treated with nitric acid, the flinty skeleton will be found to remain entire; indeed, it is said that by a careful maceration in water, a similar result may be ob-tained, and an object of most wonderful microscopic beauty be thus produced. Each individual fragment as has been shewn by Sir David Brewster, is pos-sessed of an "axis of double refraction." It will be seen, under the microscope, that the silicified cells form a coat over those longitudinal ridges, which cover the surface of the whole plant, giving it that unpleasant roughness to the touch which must be familiar to every one. In the depressions lying between the ridges are situated a large number of stomata, so that the whole anatomy is one of peculiar interest.
The proportions of silica in the ashes of several different species of the Equise-tums, are thus given by Professor Balfour:
* Newman, as well as some other botanists, incline to the opinion that it is distinct from the E. hyemale, or any British species. See " British Ferns," Edit. 2nd.
13.84 . .
E. limosum .
15.50 . .
E. hyemale .
11.81 . .
E. telmateia .
2361 . .
- an analysis, which at a glance shews us, that of our British species the E. hyemale is certainly that best adapted to the purposes of the polisher, whether or not it be identical with the "Dutch rushes." This prevalence of silicic acid in the Equisetums, is apparently the result of a combination of a silicate with that peculiar acid known as equisetic acid,* first discovered by Braconnot, in the E Telmateia of Ehrhart (the E. fluviatile of Smith, Hooker, and Babington), a fertile stem of which is represented in the woodcut.
* "Manual of Botany".
A remembrance of the rough and rigid nature of these plants will, without the aid of physiological or chemical examination, suffice to excite our surprise that any of the family should be used as human food, yet such is, nevertheless, the case; while the lower mammalia, also, in at least one instance, make choice of them. Modern writers have expressed some doubt as to the meaning of Haller, in his reference to the circumstance of the Romans eating the great horsetail;† but we need go no farther back than to the days of William Coles, who in his "Adam in Eden," to which we have before referred, tells us, as of a matter ordinarily practised, that "the young buds are dressed by some like asparagus; or, being boiled, are often strewed with flour and fried;" - being thus evidently regarded as a delicacy. Frequent have been the discussions as to whether or not horses and cows will eat these plants. One party declaring that they will not, while the other, as confidently affirms that they do; a sort of "by-play" being carried on by a third, who admit that they will devour them, but declare that they afflict them with diarrhoea, and cause the teeth - of cows, at least - to fall out.
On this point, however, though unable to speak from experience, I think we may, with the most absolute confidence, receive the state-ment of Linnaeus, at once a native of the region of which he speaks, and a calm and keen observer of nature and student of truth. And he distinctly informs us, that in Sweden the water-horsetail (E. limosum, his E. fiuviatile), is cut up as food for cows, in order to increase their milk,* just as is still done at Dunkerron; and he expresses some aston-ishment that the Laplanders should neglect to lay up a store of this plant, as well as the reindeer-moss, for their starving, winter herds; remarking that the reindeer eat it readily, even in a dry state, and when they will not eat ordinary hay.† While Mr. Knapp informs us in his "Journal of a Naturalist;" and the fact has never been disputed, that the same species (?) is the favourite food of water-rats, which appeared to frequent a certain pond for the express purpose of enjoying this food, which, like the sailor's wife of Shakespeare, they "Munched, and munched, and munched," so perseveringly, that their regular "champing" could be heard at the distance of several yards. The Equiseturas were, also, in former ages much used in medicine.
Gerarde recommends them in a bruised state for the cure of wounds, and tells us that the juice may be drunk in order to stop bleeding of the nose; and the roots boiled for coughs. Blanchard prescribes them in an infusion of plantain, to be taken night and morning, as a remedy for consumption. It is not improbable that they may possess some slightly astringent proper-ties (though these must be of a very insignificant amount); and in this light Tragus appears to view them, as he speaks of applying the expressed juice to recent and bleeding wounds, and also directs it to be put into the nostrils and on the neck, in order to stop bleeding of the nose; and that it should be taken internally in dysentery, etc. Haller, also, highly esteems it in diarrhoea and several other com-plaints; but it is almost needless to say, that it is now quite forgotten even by the most rustic prac-titioner.
GREAT HORSETAIL. Equisetum fluviatile vel Tel-matsia.
* "Ann. de Chim. et Phys.," xxxix, 10. † " Hoc fuerit equisetum. quod a plebe Romana in cibum recipitur." Hist. iii.
* "Flora Suecica".
† "Lachesis Lapponica," both as quoted by Newman, " British Ferns".
Newman, who has done so much to popularise the classification of the tribe of Filices, distinguishes ten species of the horsetail as natives of Great Britain and Ireland, which I shall, in enumerating, endea-vour to divest as much as possible of their cumbrous accumulation and confusion of synonyms: premis-ing that the distinctive appearances of the species are to be found in the nature of their fertile and barren stems, the number of the furrows or striae, and that of the teeth exhibited at those arti-culated joints where they may be divided into pieces.*
* See Balfour's "Manual of Botany".
The rough-horsetail or Dutch rush (E. hyemale, Linn.), is scarcely known in the southern and midland parts of England, and in Ireland has only, we believe, been found in the counties of Dublin and Wicklow.
The E. Mackali, Newman; (E. elongdtum of Hooker); was discovered by Mr. Mackay, in the counties of Derry and Antrim, and has since been met with in other localities in the north of Ireland, and, also, as stated by Schkuhr, in Wales. Many able botanists are, however, unable to give their assent to its separation as a distinct species, deem-ing it merely a persistent variety of the E. variega-tum, a pretty little species, which, unlike most of the family, usually grows in dry and shifting sand in the neighbourhood of the sea-shore, though it is sometimes found, as at Mucruss in Ireland, and in the Dublin canal, in fresh water. It is certainly a rather rare and local plant, and very variable in its form and mode of growth; though it less rarely becomes branched than does the E. Mackaii.
To the marsh-horsetail, E. palustre, I have already referred, as a noxious weed in the vicinity of water-courses and drains, where it sometimes becomes almost as formidable an invader as the Anacharis alsindstrum, the intrusion of which into this country has recently excited so great an alarm. Like the last named Equisetum, this species is liable to very considerable aberrations from its normal character.
The water-horsetail, E. fluviatile, Linn. (E. limo-sum of Smith, Hooker, and Babington) is a very handsome plant, of frequent occurrence in marshy places, ditches, etc. It presents the peculiarity of bearing its catkins on stems similar to the barren ones.*
But pre-eminent in grace and beauty is the ele-gant little wood-horsetail (E. sylvaticum, Linn.), so happily called "the fairy larch," † assuming, as it does, a more flexile and less rigid habit than others of the family; and forming, with its droop-ing branchlets, a great ornament to our higher woodland grounds; in the shady recesses of which it creates miniature forests of its own.
Another pretty little species, bearing a faint re-semblance to the last, is the shady-horsetail, E. umbrosum of Willdenow, or E, Drummondii of Hooker, which is very rare, having, as yet, been found in no part of the British Isles except Scot-land and Ireland. It also bears a slight resem-blance to the corn-horsetail (E. arvense, Linn.), which is not only exceedingly common in all kinds of situations, but is a most troublesome and pertina-cious weed; one of the torments of the agriculturist. It is remarkable from its being the only British species which has its fertile and barren stems posi-tively and invariably distinct, the latter not appear-ing until after the former have fructified, in the month of April.
To the E. Telmateia I have already adverted, and it is only necessary to add that this magnifi-cent and most primitive-looking plant, which is of very common occurrence, not unfrequently attains to a height of six or seven feet. For further in-formation on the distinctive characters of the British species, I must refer the student to the masterly exposition of Newman;* and shall simply add that the botanical name is taken from the Latin equus, a horse, and seta, a hair or bristle; thus correspond-ing with the popular name borne by the plant almost throughout Europe.
* Hooker "British Flora".
† See Johnston's "Botany of E. Borders".
* "British Ferns." Edit. 2.