Rati Syii, Grit. 4. Hsskbje capillares et affines. 
EQUISETUM itrvtn/e fcapo fruaificante undo ; fterili fkmdofo. Lin. Syft. Vtgitab. p. 457 
1516. FI. Suec. 11. 928. 
EQUISETUM caule florigero nudo, fterili verticillato, radiorum duodecim. Haller. Hifi. n. 
EQUISETUM arvenfe. Scopoli FI. Carn. n. 1253. 
EQUISETUM arvenfe longioribus fetis. Baub. Pin. 16. Parkins. 1202. Rail Hifi. p. 130. 
Horfe-tail. 
EQUISETUM fegetale. Ger. em ac. 1x14. 
HIPPURIS mitior cum flore. Dod. Pempt. p. 73. 
EQUISETUM minus terreftre. L B. IIP 730. Hudfon. FI. Angi. ed. 2. p. 265. Lightfoot FI. Scot . 
p. 647. 
Sp. Pl. p. 
676. 
Corn 
ROOT perennial, {lender, black, jointed, exceedingly 
creeping, with tufts of black fibres fpringing 
from the joints. 
STALKS producing the feeds fpringing up before the 
leaf-ftalks, and foon withering, the thicknels 
of a large wheat-ftraw, a handVbreadth or 
more in height, upright, naked, yellowifli, 
jointed ; joints from two to five, covered with 
membranous, ribbed {heaths, divided at top into 
numerous fegments or teeth. 
SEED-SPIKES terminal, oblong, obtufe, about an inch 
in length. 
CAPSULES, or feed-cafes, numerous, angular, upright, 
placed together round a partial receptacle, and 
covered with a yellowifti orbicular ftiield, fig. 1. 
finally opening inwardly, and throwing out a 
greenifh powder, fig. 2. 3. magnified, fig. 4. 
STALK a foot or more in height, in open fituations 
oblique, ftriated, rough ifti, jointed. The Sheaths 
numerous and toothed. 
LEAVES whirled, about eight in each whirl, Ample, 
and like the ftalk. 
RADIX perennis, gracilis, nigra, articulata, infigniter 
reptans, fibris nigricantibus e geniculis exortis 
capillata. 
SCAPI feminiteri ante caules frondofos prodeuntes, et 
cito marcefcentes, cralfitie culmi triticei ma- 
joris, palmares aut dodrantales, eretfti, nudi, 
lutelcentes, geniculati, geniculis 2. 3. 5. vagi- 
nis multifidis, nervofis, membranaceis, cir- 
cumveftiti. 
SPICAE feminiferx terminales, oblongae, obtufic, un- 
ciales. 
CAPSULrE feu thecae feminiferre plurimae, angulatae, 
ere£be, circa receptaculum proprium collocatur, 
et fcuto orbiculato lutefeente te£he, fig. 1. de- 
mum introrfum dehilcentes et pulverem viref- 
centem effundentes, fig. 2. 3. au6i. fig. 4. ^ 
CAULIS pedalis et ultra, in apricis obliquus, ftriatus, 
lcabriufculus, geniculatus. Vagina: numerofas, 
denticulatae. 
FOLIA verticillata, oifto circiter in fingulo verticillo, 
fimplices, cauli fnnplices. 
Experiment and ohfervation', which have difeovered perfect feeds, if not real Stamina and Piftilla, in fome of the 
plants of this hidden clafs, have hitherto failed in afeertaining what the powder is, which is contained in fuch 
abundance in the fpikes of the Horfe-tail, different Botanifts differing widely in their opinions concerning it. 
LiNNiEus and Scopoli conlider it as the true feed of the plant : Haller and Adanson as the male duft ; and fo 
ftronpiv was the laft mentioned author of this opinion, that he removed it from the cryptogamous plants, and 
placed it with the family of the pines, from which, however, as Scopoli very judicioufly oblerves, it differs toto 
ccelo. 
We fat down to examine the fructification of this plant, in full expectation of finding Pollen not Seed contained 
in its cells. We conceived, a priori , that a fubftance fo delicately formed, and fo rapid in its growth, could fcarcely 
produce capfules with ripe feeds ; but we role from our examination in the full belief of the powders being the 
real feed, fo far as we could judge from its ftrudure and ceconomy : actual vegetation muft however be proved, 
before we can arrive at certainty in this matter. 
If a little of the powder be ihaken out of the fpike on a piece of white paper, a moderate magnifier difeovers a 
motion in it, el'pecially if it be breathed on. A fimilar motion is obferved in the capfules of the Ferns when they 
throw out their feeds ; and in the fine powder contained in the heads of the Jungermannia, if we apply a very 
confiderable magnifier to this powder, we find its motion arife from a very different principle from that which 
actuated the two former. Here every particle of the powder has three or four, very rarely five, fine, pellucid 
threads, which are club-Ihaped at the extremity. Thefe threads are elaftic, and, by varioufly extending and curling 
themfelv.es up, occafion the motion which is fo perceptible. Monf. Adanson, who has minutely deferibed this 
iced as pollen, compares the appearance it fometimes aflumes to a fpider with its legs ftretched out. Although thefe 
motions, which are extremely lingular and diverting, are plainly been with a good magnifier, we never could 
di (cover the bodv of the feed to make any fort of explofion as Pollen would, under fimilar circumftances of expofure. 
The proper time to examine this curious phenomenon is in April, when the plant produces its fpikes. 
The medicinal virtues of the Equiletuni are too problematical to deferve notice. Writers on the Materia Medica 
rank it with the aftringents. 
The Farmer is deeply interefted in a knowledge of this plant, as it is not only one of the rnoft troublefome and 
difficult weeds to extirpate that we are acquainted with, but noxious even to cattle, efpeciallv kine. Haller 
relates a particular cafe in which it proved fatal to a young heifer, by bringing on an incurable Diarrhcea. 
Many parts of BatterJ'ea Fields exhibit this plant in perfection. It fometimes is found in meadow's and under 
hedges ; and, according to its fituation, like all other plants, aflumes a variety of appearances. 
