Mutations 221 
governed by Natural Selection, just as much as the specialisation of 
the rostellum in an Orchid, or of the pappus in a Composite. 
Did space allow, other examples might be added. We may 
venture to maintain that the glimpses which the fossil record allows 
us into early stages in the evolution of organs now of high systematic 
importance, by no means justify the belief in any essential distinction 
between morphological and adaptive characters. 
Another point, closely connected with Darwin’s theory, on which 
the fossil history of plants has been supposed to have some bearing, 
is the question of Mutation, as opposed to indefinite variation. 
Arber and Parkin, in their interesting memoir on the Origin of 
Angiosperms, have suggested calling in Mutation to explain the ap- 
parently sudden transition from the cycadean to the angiospermous 
type of foliage, in late Mesozoic times, though they express themselves 
with much caution, and point out “a distinct danger that Mutation 
may become the last resort of the phylogenetically destitute”! 
The distinguished French palaeobotanists, Grand’ Eury/and Zeiller?, 
are of opinion, to quote the words of the latter writer, that the facts 
of fossil Botany are in agreement with the stidden appearance of 
new forms, differing by marked characters from those that have given 
them birth; he adds that these results give more amplitude to this 
idea of Mutation, extending it to groups of a higher order, and even 
revealing the existence of discontinuous series between the suc- 
cessive terms of which we yet recognise bonds of filiation®. 
If Zeiller’s opinion should be confirmed, it would no doubt be a 
serious blow to the Darwinian theory. As Darwin said: “Under a 
scientific point of view, and as leading to further investigation, but 
little advantage is gained by believing that new forms are suddenly 
developed in an inexplicable manner from old and widely different 
forms, over the old belief in the creation of species from the dust of 
the earth*.” 
It must however be pointed out, that such mutations as Zeiller, 
and to some extent Arber and Parkin, appear to have in view, bridging 
the gulf between different Orders and Classes, bear no relation to 
any mutations which have been actually observed, such as the com- 
paratively small changes, of sub-specific value, described by De Vries 
in the type-case of Oenothera Lamarckiana. The results of palaeo- 
botanical research have undoubtedly tended to fill up gaps in the 
Natural System of plants—that many such gaps still persist is not 
1 C, Grand’Eury, ‘Sur les mutations de quelques Plantes fossiles du Terrain houiller.” 
Comptes Rendus, cxum. p. 25, 1906. 
7B. Zeiller, “Les Végétaux fossiles et leurs Enchainements,” Revue du Mois, m1. 
February, 1907. 
5 loc. cit. p. 23. $ Origin of Species, p. 424, 
