480 RELATIONS TO EXISTING VEGETABLES. 
ing the vegetables which gave origin to coal are, 
1st, that a large proportion of these plants were 
vascular Cryptogamiae, and especially Ferns ; 
2dly, that among these Cryptogamic plants, the 
Equisetacese attained a gigantic size ; 3rdly, that 
Dicotyledonous plants, which compose nearly 
two-thirdsof living Vegetables, formed but a small 
proportion of the Flora of these early periods.* 
4thly, that although many extinct genera, and 
certain families have no living representatives, 
and even ceased to exist after the deposition 
of the Coal formation, yet are they connected 
with modern vegetables by common principles 
* The value to be attached to numerical proportions of fossil 
Plants, in estimating the entire condition of the Flora of these 
early periods, has been diminished by the result of a recent inte- 
resting experiment made by Prof. Lindley, on the durability of 
Plants immersed in water. (See Fossil Flora, No. xvii. vol. iii. 
p. 4.) Having immersed in a tank of fresh water, during more 
than two years, 177 species of plants, including representatives 
of all those which are either constantly present in the coal mea- 
sures or universally absent, he found : 
1. That the leaves and bark of most dicotyledonous Plants are 
wholly decomposed in 2 years, and that of those which do resist 
it, the greater part are Conifer ce and Cycadece. 
2. That Monocotyledons are more capable of resisting the 
action of water, particularly Palms and Scitamineous Plants ; 
but that Grasses and Sedges perish. 
3. That Fungi, Mosses, and all the lowest forms of Vegetation 
disappear. 
4. That Ferns have a great Power of resisting water if gathered 
in a green state, not one of those submitted to the experiment 
having disappeared, but that \\\e.\x fructijication perished. 
Although the Results of this experiment in some degree in- 
