INVESTIGATION OF FOSSIL PLANTS. 61 
embryo lies, hence they are sometimes named Synorhiza. 
The veins of the leaves (in those whose leaves are veined), 
are either simple or forked ; in which respect they approach 
the endogens on the one hand, and the acrogens on the 
other. 
This concise definition of the natural divisions of the 
vegetable kingdom will enable the reader to comprehend the 
botanical principles which must guide him in his attempt to 
explore the ancient floras, whose fossil remains are generally 
found in a very fragmentary condition. 
I need only add that M. Ad. Bronginart, in his great 
work on Fossil Plants, arranges the vegetable kingdom into 
five classes, viz. :— 
1. Cellular Cryptogamia,* or Amphigens. 
2. Vascular Cryptogamia,t or Acrogens. 
3. Monocotyledons.{ 
4. Gymnospermous Dicotyledons.§ 
5. Angiospermous Dicotyledons.|| 
ON THE MODE OF INVESTIGATING FOSSIL REMAINS OF 
VEGETABLES. 
The distinguished authors of the British Fossil Flora 
justly remark, that a few isolated, and very imperfect data, 
exclusively afforded by the remains of the organs of vegeta- 
tion, are but too often the sole guide to the class, order, or 
* Plants having the fructification concealed, and of cellular struc- 
ture only. 
+ Plants having the fructification concealed, and with vessels, or 
vascular tissue. 
+ Flowering plants with one cotyledon ; the Endogens. 
§ Plants with naked seeds ; that is, destitute of a pericarp or case. 
|| Plants with the seeds ina receptacle or pericarp, with a style 
and stigma. 
