Ancestry of Angiosperms 313 
of temperate regions; on the other hand palaeontological discoveries 
have put the problem in an entirely new light. Well might Darwin, 
writing to Heer in 1875, say: “Many as have been the wonderful 
discoveries in Geology during the last half-century, I think none have 
exceeded in interest your results with respect to the plants which 
formerly existed in the arctic regions’.” 
As early as 1848 Debey had described from the Upper Cre- 
taceous rocks of Aix-la-Chapelle Flowering plants of as high a 
degree of development as those now existing. The fact was com- 
mented upon by Hooker?, but its full significance seems to have been 
scarcely appreciated. For it implied not merely that their evolution 
must have taken place but the foundations of existing distribution 
must have been laid in a preceding age. We now know from the 
discoveries of the last fifty years that the remains of the Neocomian 
flora occur over an area extending through 30° of latitude. The con- 
clusion is irresistible that within this was its centre of distribution 
and probably of origin. 
Darwin was immensely impressed with the outburst on the world 
of a fully-fledged angiospermous vegetation. He warmly approved 
the brilliant theory of Saporta that this happened “as soon [as] 
flower-frequenting insects were developed and favoured intercross- 
ing’.” Writing to him in 1877 he says: “Your idea that dicoty- 
ledonous plants were not developed in force until sucking insects 
had been evolved seems to mea splendid one. I am surprised that 
the idea never occurred to me, but this is always the case when 
one first hears a new and simple explanation of some mysterious 
phenomenon‘.” 
Even with this help the abruptness still remains an almost insoluble 
problem, though a forecast of floral structure is now recognised in some 
Jurassic and Lower Cretaceous plants. But the gap between this and 
the structural complexity and diversity of angiosperms is enormous. 
Darwin thought that the evolution might have been accomplished 
during a period of prolonged isolation. Writing to Hooker (1881) he 
says: “Nothing is more extraordinary in the history of the Vegetable 
Kingdom, as it seems to me, than the apparently very sudden or 
1 More Letters, 1. p. 240, 2 Introd. Essay to the Flora of Tasmania, p. xx. 
3 More Letters, 1. p. 21. 
4 Life and Letters, m1. p. 285. Substantially the same idea had occurred earlier to 
F. W. A. Miquel. Remarking that “sucking insects (Haustellata)...perform in nature 
the important duty of maintaining the existence of the vegetable kingdom, at least as far 
‘as the higher orders are concerned,” he points out that “the appearance in great numbers 
of haustellate insects occurs at and after the Cretaceous epoch, when the plants with 
pollen and closed carpels (Angiosperms) are found, and acquire little by little the pre- 
ponderance in the vegetable kingdom.” Archives Néerlandaises, 11. (1868). English 
translation in Journ. of Bot. 1869, p. 101. 
