CALAMITES. 
4 (JO 
Torrid Zone, its species are most abundant in 
the temperate zone, decrease in size and niiiH' 
her as we approach the regions of cold, aiiJ 
arrive at their greatest magnitude in the warm 
and humid regions of the Tropics, where theii’ 
numbers are few. 
M. Ad. Brongniart* has divided fossil Equise- 
tacem into two Genera ; the one exhibits the cha- 
racters of living Equiseta, and is of rare occur- 
rence in a fossil state ; the other is very abun- 
dant, and presents forms that differ materially 
from them, and often attain a size unknown 
» 
among living Equisetaceae ; these have been 
arranged under the distinct genus Culamites,] 
they abound universally in the most ancient Coal 
formation, occur but sparingly in the lower strata 
of the Secondary series, and are entirely M^antiog 
in the Tertiary formations, and also on the actual 
surface of the earth. 
The same increased development of size, whicli 
in recent Equisetaceae accompanies their geogra- 
* Histoire des Vegetaux Fossiles, 2nd Livraison. 
t Calamites are characterized by large and simple cyli”' 
drical stems, articulated at intervals, but either without shcoth^^ 
or presenting them under forms unknown among existing Eq"*' 
seta : they have sometimes marks of verticillated Branches around 
their articulations, the leaves also are without joints. But tb® 
most obvious feature wherein they differ from Equiseta, is (heif 
bulk and height, sometimes exceeding six or seven inches in 4>n' 
meter, whilst the diameter of a living Equisetum rarely exceed® 
halt an inch. A Calainite fourteen inches in diameter has latel'' 
been placed in the Museum at Leeds. 
