of the Conifer oc. 317 
and Norway : All of which perish, or at most serve only to 
enrich the collections of the naturalist. 
1. The whole of these Coniferous tribes are social, natural- 
ly occupying immense continued tracts, almost to the exclu- 
sion of all other trees of a distinct race, which they injure, 
and frequently choke ; an important lesson to planters, who 
are fond of mixing these lofty inhabitants of the forest with 
oaks, elms, and other strangers. Even in this country our 
native pine (Pinus sylvtstris), where not prevented by oppo- 
sing culture, spreads its seeds on every side, and would eventu- 
ally re-establish the ancient forests. 
S. The social disposition, indeed, extends to the more dis- 
tantly related tribe of EpHEDEACEiE, in which we must, from 
the most evident marks of affinity, include Equisetum, which 
Jussieu, in his admirable work, has at present ranked with the 
Filices. The still obscure history of the germinating process, 
and even our imperfect views of the parts of the fructification in 
these plants, ought not to oppose conclusions so strongly war- 
ranted by other characters. 
3. Even externally the stems in Thuia and Cupressus, when 
young, are distinctly marked with nodes at intervals, surround- 
ed with squamiform dentated leaves, analogous with the den- 
tated sheaths surrounding the joints of Equisetum, Cassuarina, 
and Ephedra. 
4. A perpendicular section of a bud in Thuia affords a dis- 
tinct view of the structure of the first shoots of the approaching 
season ; the whole resembling a series of cones included within 
each other, gradually decreasing in size towards the centre, 
from which the first shoot is evolved. 
These buds are successively evolved during the progress of the 
season, whilst others are continually shooting from their centre, 
and from the abundant sap, burst from the sides of the various 
nodes in verticils, particularly in moist soils. 
5. Each node in the true verticillated Cupressi, Sabinse, 
Thuia?, Equiseta, Ephedra, and Cassuarinae, is accompanied 
with its respective ciliated or dentate sheath which in Equisetum 
forms a complete circle ; in Ephedra there are two teeth only, 
in Thuia four. Thuia articulata, figured by Desfontaines % 
* Flora Atlaniica., t. 252. 
VOL. I. XO. OOTOEEE 1819. Y 
