400 lycopodiace.t:. 
Lepi(lodeiidro7u * 
The genus Lepidodendron comprehends many 
species of fossil plants, which are of large size, 
and of very frequent occurrence in the Coal for- 
mation. In some points of their structure they 
have been compared to Coniferae, but in other 
respects and in their general appearance, with 
the exception of their great size, they very much 
resemble the Lycopodiacece^ or Club Moss Tribe. 
(See PI. 1. Figs. 9. 10.). This tribe at the pre- 
sent day, contains no species more than three 
feet high, but the greater part of them are weak, 
or creeping plants, while their earliest fossil re- 
presentatives appear to have attained the dimen- 
sions of Forest Trees.t 
Existing Lycopodiaceae follow nearly the same 
law as ferns and Equisetaceae, in respect of geo- 
graphical distribution ; being largest and most 
abundant in hot and humid situations within the 
Tropics, especially in small islands. The belief 
that Lepidodendra were allied to the Lycopo- 
* PI. 1. Figs. 11. 12. and PI. 55, Figs. 1. 2. 3. 
f Prof. Lindley states that the affinities of existing Lycopo- 
diacese are intermediate between Ferns and Coniferse on the one 
hand, and Ferns and Mosses on the other; They are related to 
Ferns in the want of sexual apparatus, and in the abundance of 
annular ducts contained in their axis; to Coniferae, in the aspect 
of the stems of some of the larger kinds ; and to Mosses in their 
whole appearance. 
