718 Hens low .— The Origin of Monocotyledons fro7n Dicotyledons , 
4 theory ’, as I then called it, was not experimentally verified. Several 
corroborative experiments, however, have been made since; which prove 
incontestably that the special and hereditary, acquired characters residing 
in the roots, stems, and leaves of Monocotyledons are precisely the same 
as those which arise in Dicotyledonous plants, when responding to an 
aquatic environment, whether seen in Nature or in artificial experiments at 
the present day. Therefore, one need not entirely rest satisfied with 
Induction, or the accumulation of a very large number of coincidences, 
all of which conspire, more or less independently, to establish the conclusion 
herein maintained. 
Since my former paper was published, numerous other coincidences 
have been noticed, so that my present object is to supplement that paper, 
and thereby to strengthen the argument with addenda , fortified by experi¬ 
ments. 
% Evidences from Geology. 1 
During the last twenty years much new knowledge has been acquired 
about fossil plants. The researches of Prof. Seward, Dr. Scott, and others 
have been ably put before us. For instance, Dr. Scott thus writes with 
regard to the relationship between Monocotyledons and Dicotyledons : 
‘ If the Angiosperms were derived from the Cycadophyta, it would appear to 
follow that the Dicotyledons were first evolved, for their structure has 
clearly much more in common with the Cycad type than that of Monoco¬ 
tyledons. The latter would thus be regarded as a branch line of descent, 
diverging, no doubt at a very early stage, from the main Dicotyledonous 
stock. This view has been maintained, on other grounds, by various 
modern botanists. So far, however, as the palaeontological record shows, 
the two classes are of almost equal antiquity, both appearing for the first 
time in Lower Cretaceous rocks.’ 2 
The reason of our great absence of knowledge of plant life during the 
Secondary Epoch is because the Liassic and Oolitic series of strata are 
almost entirely marine; so that countless ages passed, during which we 
know comparatively little of the land floras. 
As exceptions to this statement, the i Dirt-bed ’ of the Purbecks, 
which I investigated many years ago, is very rich in plant remains ; and 
Dr. Scott reminds me of the American deposits which are extraordinarily 
rich, being contemporary with our own Oolites. Still, taking all the plant 
beds known of the Secondary Epoch, they do not amount to very much in 
1 See loc. cit., p. 486. Similar references are always to my former paper. 
2 Studies in Fossil Botany, Pt. II, p. 660. 
