EQUISETUM HYEMALE. ROUGH HORSE-TAIL,
OR SHAVE-GRASS.
EQUISETUM hyemale; caulibus simplicibus erectis scaberrimis apice spiciferis, vaginis discoloribus
basi apiceque sphacelatis, dentibus aristatis omnino caducis. TV■
EQUISETUM hyemale. Linn. Sp. P I. p. 1517. Huds. Angl. p. 448. L ig h tf Scot. p. 650.
fr ith . Bot. A r r . ed. 4. ml. 3. p. 740. FI. Dan. 1 .1409. Hoffm. Germ. ed. 2. ml. 2.
p . 2. Willd. Sp. PI. ml. 5. p. 8. Smith FI. B r it. p. 1105. Engl. Bot. t. 915.
Schkuhr Fil. t. 172. Decand. FI. Fr. ed. 3. ml. 2. p. 580. FI. Gall. Syn. p. 118.
fVahl. FI. Lapp. p. 299. Aiion H ort. Kew. ed. 2. ml. 5. p. 492. Pursh FI. Amer.
Sept.p. 652. Hook. FI. Scot. P . II. p. 161. Iceland Tour, ml. 2. p. 336.
EQUISETUM caule subnudo asperrimo, vaginis caulinis indivisis, ramis ciliatis. Hall. Helv. n. 1679*
EQUISETUM nudum. Naked Horsetail. Raii Syn. p. 131. t. 5 . f 2.
Dan. Shavgrees. Dut. Winterigpaardestaart. Fr. L a Prele dCh'mcr. Germ. De r Schachtelhalur.
Norw. Skieste. Span. Sk'dfe.
Class a n d Or d e r . CRYPTOGAMIA GONOPTERIDES, Willd. CRYPTOGAMIA
FILICES, Linn.
[N a tu r a l O r d e r . EQUISETACE^E, Rich., Decand., Hook. FILICES, Juss^\
G e n . Ch a r . Receptacula peltata, plana, polygona, spicata, subtus Indusiis quatuor ad septem corniculatis
clausis, tandem longitudinaliter rumpentibus, e t fructificationes occultantibus, obsita. Stamina quatuor. Ger-
men ovatum. Stylus nullus. Semen unicum. TV.
Gb n . Ch a r . Receptacles peltate, plane, polygonous, spiked, beneath having from four to seven closed
corniculated Involucres; at length longitudinally bursting, covering the fructifications. Stamens four. Germen
ovate. Style none. Seed single.
Ra d ix (vel Caudex subterraneus) longe repens, nigra,
articulata, sulcata, densissime fibroso-tomeutosa.
Caules plures ex eadem radice, sesquipedales et ultra,
simplicissimi, erecti, teretes, nudi, glauco-
virides, rigidi, fistulosi, articulati, sulcati, sulcis
asperis, inter sulcos lineis elevatis transversim car-
tilagineo-verruculatis scabratis: Articuli longi,
superne vaginantes: Vaginas cylindrace®, ni-
grae, basin versus annulo pallide tusco vix albo,
apice suboctodentato, dentibus subulatis cito de-
ciduis, et tunc vaginas obtusissime crenatas; inferiores
omnino nigrae.
S p ic a (seu Amentum) solitaria, terminals, subsessilis,
oblongo-ovata, parva, primum nigra demum
fusca, e squamis numerosis peltatis, polygonis,
pedicellatis constans.
I nvolucra plerumque quinque, sub pelta affixa, pen-
dentia, intus dfehiscentia. _
Semina (?) numerosa, fusco-viridia, sphterica, filamentis
quatuor apice incrassatis granuliferis, primum
circa semen arete convolutis, demum elastice se
exporrigentibus, instructa.
Root (or subterranean Stem) creeping for a great length,
black, jointed, furrowed, thickly covered with
downy fibres.
Stems many from the same root, a foot and half and
upwards in height, quite simple, erect, rounded,
naked, o f a glaucous green, rigid, hollow, jointed,
furrowed, the furrows rough, between the furrows
having transverse elevated lines studded
with cartilaginous wa rts: Joints long, sheathed
above : Sheaths cylindrical, black, having round
their base a pale brown almost white ring, their
points cut into about eight teeth, the teeth awl-
shaped, soon falling off, and leaving the sheaths
bluntly crenate ; the lowest ones wholly black.
Sp ik e (or Calkin) solitary, terminal, nearly sessile, o f
an oblong-ovate form, small, first black subsequently
brown, consisting o f numerous peltate,
many-sided, pedicellate scales.
Involucres commonly five, fixed beneath the scale,
pendent, bursting internally.
S e ed s (?)numerous, dark green, spherical,furnished with
four filaments which are granuliferous, thickened
at the points, at first closely rolled round the
seed, then throwing themselves off with an elastic
force.
Fig. A. Portion of the upper part of a stem, with its spike of fructification. Fig. B. Portion of the stem to show
the structure of the. Epidermis. Fig. 1. Scale of the spike. Fig. 2. The same, showing more distinctly the
Involucre. Fig. 3. Seeds (?) with their spiral filaments. Fig. 4. Single seed, with its filaments, as at Jig. 3,
spirally twisted. Fig. 5. Seed with its granule-bearing filaments untwisted :— all more or less magnified.
This is rather a rare inhabitant of moist woods in the midland and northern parts of the kingdom, but is not
found in any of the southern counties, except in Wiltshire, where Ray says that he met with it plentifully in a
rivulet near Broadstitch Abbey. In Scotland it is not of frequent occurrence. Dr. Stoke found it near Lanark;
Sir James E. Smith' between Lasswade and Meavis Bank, Edinburgh; Mr. Arnott by the side of George-town
burn, Cleish, in Kinross-shire; and Mr. Brodie in Darnaway Forest, and in a copse by the town of Forres, Morayshire,
at which last place, in August 1822, I gathered the specimens here figured.
The cuticle of this species of Equisetum presents a curious appearance when viewed through the microscope,
having the elevated lines, which form the spaces between the furrows, marked with transverse, prominent, rigid,
glass-like warts, rough to the touch, and which cause the epidermis to act like a file. Hence the important value
of the plant, which is largely exported from Holland, and under the name of Dutch Rushes is sold in this country
for the polishing of wood, bone, ivory, brass, &c. This property is due to a quantity of siliceous earth which Sir
Humphry Davy first detected, and which he found generally to exist in the epidermis of hollow-stemmed plants,
principally in that of the Rattan Cane (Calamus Rotung), which contains a sufficient portion of flint to afford sparks
when struck with a steel. . . . . . *
In Northumberland the dairy-maids scour and clean their milk-pails with the stems of the Rough Horsetail.
Wretched must be the condition of cattle doomed to feed upon this flinty plant, which is the case with the
ill-fated animals in Iceland. I t seems, however, to have been ascertained, that, while to sheep it proves injurious,
and that the teeth of the cows who eat it soon fall out, it is wholesome for horses. As far, however, as the
latter animals are concerned, Nuttall gives a different statement, observing that the Equisetum hyemale is abundant
on the banks of the Missouri, below the Platt, in North America, and is called Rushes; and that it is found to be
hurtful to horses, if they browse upon it for any considerable length of time.
As a species, it is very distinct from the other native Equiseta of Britain ; the rare E. variegatum is similar
to it in the rough quality, but is a vastly smaller and more yellow-green plant, with stems much branched below,
anu, according to Smith, with white teeth on the sheaths.