HORSETAILS. 
Ill 
thus corresponding with the popular name borne by 
the species throughout Europe. Sir William Hooker 
describes nine species as native in Britain, and some 
of them are pretty though curious-looking plants. 
They are leafless and have stems divided by points, 
each of which terminates in a toothed sheath. The 
fructification is contained on capsules arranged in 
cones. The outer skin of the stems abounds in flinty 
particles, placed in rows which form ridges up the 
stem. The hollows between these ridges contain 
minute openings or stomata. This group of plants 
carries us back in thought to the days of the early 
world when the earth was peopled by the strange 
monsters whose history is written on their rock-en¬ 
tombed bones and clothed with a vegetation of which 
these Horsetails are the type. At that period of the 
world’s history they grew as trees, and formed shelter 
for the huge beasts whose forms are only known to us 
by their remains, such as the Sauroids, and the mighty 
Plesiosaurus, and Megalosaurus, of which we read in 
geological records. Even at the present time many 
of these plants which We see here only in their 
diminutive size, attain in the climate of Brazil and 
other warm regions a height of fifteen or eighteen feet 
and a diameter of six or seven inches. The stems of 
our British species of Equisetacese contain so much 
flinty matter that they are still used in many parts of 
the country as scouring paper to clean brass and 
wooden vessels. Formerly no comb-maker, metal 
