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 1 ." 



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 2 , 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 3 ." 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 me a 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 4 ." 



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, n. p. 240. - Introd. Essay to the Flora of Tasmania, p. xx. 



3 More Letters, n. p. 21. 



4 Life and Letters, in. p. 285. Substantially the same idea had occurred earlier to 

 F. W. A. Miquel. Kemarking 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 Neerlandaises, m. (1868). English 

 translation in Journ. of Bot. 1869, p. 101. 



