NUMBKllS OF FOSSIL AND RECENT PLANTS. 521 
vascular Cryptogamic plants. Among existing 
vegetables almost two thirds are Dicotyledonous. 
The Remains of Monocotyledonous Plants oc- 
cur, though sparingly, in each Period of Geolo- 
gical formations. 
The number of fossil plants as yet described is 
about five hundred ; nearly three hundred of 
these are from strata of the Transition series ; 
and almost entirely from the Coal formation. 
About one hundred are from strata of the Secon- 
dary series, and more than a hundred from for- 
mations of the Tertiary series. Many additional 
Species have been collected from each of these 
series, but are not yet named. 
As the known species of living vegetables are 
more than fifty thousand, and the study of fossil 
hotany is as yet but in its infancy, it is probable 
that a large amount of fossil species lies hid in 
the bowels of the earth, which the discoveries of 
each passing year will be continually bringing to 
Hght. ‘ 
The plants of the First period are in a great 
measure composed of Ferns, and gigantic Equi- 
setaceae ; and of families, of intermediate charac- 
ter between existing forms of Lycopodiacese and 
Coniferas, e. g. Lepidodendriae, Sigillariae, and 
^tigmariae ; with a few Conifei’ae. 
Of plants of the Second period, adiout one third 
formations present only that peculiar tribe of this class, which is 
®ade up of Cycadese and Conifer®, viz. Gymnospermous Pha- 
nerogami®. 
