Plate 60. 
EQTJISETUM arvense, Linn. 
Field Horse-tail. 
Equisetum (§ Vernalia) arvense; sterile stems slightly scabrous, ending in along 
tail-like point, erect or often procumbent, deeply sulcated with twelve to 
fourteen furrows, copiously branched with simple erecto-patent four-sided 
branches; fertile stems stouter but much shorter than the sterile ones, 
without branches; sheaths rather distant, tubuloso-infundibuliform, white 
and scariose, with about twelve brown striae and as many lanceolate-acumi¬ 
nate sharp brown teeth; peduncle of the oblong-cylindrical spike more or 
less elongated. 
Equisetum arvense. Linn. Sp. Pl.p. 1516. SchJc. Ml. v. 1. p. 167. Willd. Sp. PI. 
v. 5.j v. 1. Png. Pot. t. 2020. Bolt. Pil.p. 62. t. 34. Sm. Png. PI. v. 4. 
p. 339. Newm. Brit. Ferns, p. 77 {with figures). Hook, and Am. Brit. 
PI. ed. 8. p. 600. Vaucli. Monogr. des Presles, p. 33. t. 1. Duval-Jouve % 
in Bull. Soc. Bot. v. 5 . p. 515./. 1. Cosson, FI. des Pnv. de Paris, p. 877. 
Equisetum arvense, longioribus setis. Raii Syn. p. 130. 
Hab. Meadows, pastures, and cornfields throughout the kingdom; abundant,— 
so much so, that it ranks among the mauvaises herbes , and is very trouble¬ 
some to the farmer, not only as difficult to eradicate, but, according to Mr. 
Curtis, noxious to cattle, especially to kine. Sir James Smith presumes 
that its action on their intestines may be chiefly mechanical, considering the 
sharp rough angles and points with which the whole plant abounds, and the 
abundance of flinty earth in its cuticle, which forms a file, similar to though 
finer than P. hyemale. 
Like most plants of wide geographical distribution (and this 
we receive not only from almost every part of Europe and North 
America, as far north as the Mackenzie River, from India, chiefly 
northern, China, etc.), it is liable to vary in size and form and 
disposition of the branches. The sterile stems are erect or pro¬ 
cumbent, the caudate apex is sometimes not developed, and then 
it approaches very near E. umbrosum. Even more than on E. 
umbposum , the sterile stem is apt to bear a spike of fructification, 
or the fertile plant throws out branches, and thus apparently be¬ 
comes perennial. 
Plate 60. Fertile frond and upper portion of a sterile frond of Pquisetum 
arvense , Linn.,— natural size. Fig. Portion of a transverse section of the stem, 
showing the lacunes,— magnified. 
