CALAMITES. 107 
Cauamites. ign. 14, 15.—Stem articulated, regularly 
furrowed longitudinally, the articulations naked, or studded 
with tubercles. 
The plants of this genus were supposed to be related to 
the marestail, but to differ in the absence of the encircling 
sheaths, and in being uniformly striated; but an examina- 
tion of specimens in a better state of preservation than 
those previously known, shows their affinity to the gymne- 
sperms. Some of the species are of a gigantic size, being 
from one to three feet in diameter, and from thirty to 
forty feet in height. Calamites abound in the coal forma- 
tion, and must have constituted an important feature in 
the forests of the carboniferous period ; they occur also 
in more ancient deposits, and some species belong to the 
earliest terrestrial Flora of which any vestiges are known. 
In most instances when specimens are found lying in the 
same plane with the strata, 
they are pressed flat, but those 
occurring in a vertical posi- : 
tion retain their natural cylin- ‘ @ 
drical form. An outer crust or [ 
cylinder of coal generally in- 
vests the stem, but traces of the 
internal structure are rarely 
preserved. 
The Calamite consists of a 
large central column of tissue, Licn. 14. CALAMITES DECORATUS. 
surrounded by a ligneous cy- in 
linder. The central part has in Ad: BrORR ANE | Sra 
° : Coal Formation. Yorkshire. 
most instances perished after 
Fic. ].—Part of a stem, showing the 
the death of the plant,and the ~~ tubercles for the attach- 
] ft been filled u ment of leaves. 
ety ae left Ls 2.—A portion of the same on a 
with mineral matter. As the larger seale. 
hollow ligneous zone is almost 
always carbonized, and very friable, it is seldom attached 
