FOSSIL FERNS. 109 
which surrounded the joint: this character is entirely dis- 
tinct from the sheath of the Equisetum shown in Lign. 12. 
This specimen points out the importance of carefully exam- 
ining and preserving the stone around fossil stems ; had this 
precaution been lost sight of in this instance, no knowledge 
would have been obtained of this important botanical cha- 
racter. It is rarely that any traces of the roots remain ; the 
fossil figured (jig. 2) is from the Foss. Flor. A beautiful 
example of the foliage of a species of Calamites is repre- 
sented in Lign. 59, fig. 2. 
Upright stems of Calamites occur in the Coal formation 
near Pictou, in North America; and in one example a 
group of ten or twelve stems, covering an area of two square 
feet, sprung from one root.* 
FILICITES, OR FERNS. 
We now arrive at the consideration of one of the most 
interesting families of the vascular cryptogamia that 
adorned the Flora of the ancient world, and the living 
species of which impart beauty and elegance to the scenery 
of the countries where they prevail. The most essential 
character of these vegetables, is that of developing their 
fructification on the leaves; a fact familiar to every one 
who has even but cursorily examined the Polypody grow- 
ing on our walls, or the Brake of our hedge-rows and 
commons. The largest species of British ferns scarcely 
exceed four or five feet in height ; but the arborescent or 
tree-ferns, of warm climates, attain an altitude of from 
thirty to forty feet. There is too this peculiarity in the 
arborescent forms, that while in our indigenous species the 
leaves surround the stem, and incline towards the upper 
part of the plant, the foliage of the former bends downwards, 
* Dawson, Geol. Proc. vol. vii. p. 195. See Sir C. Lyell’s Travels 
in North America, vol. ii. p. 195. 
