21 5 
Willis.—Age and Area. 
names is made, and it is shown that they have followed rules similar to Age 
and Area and Size and Space. 
Some statistics are given of various British floras published from 1782 to 
1908, and it is shown that the curves for sizes of genera for ten floras of this 
period agree very closely indeed with one another. 
The next section is concerned with the distribution of genera by sizes 
in definite areas. Among other things it is shown that the nearer to the 
mainland an island is, the larger is the proportion of monotypes (usually 
supposed relics) among its endemic genera—a very difficult phenomenon 
for the advocate of relicdom to explain. 
Further illustration of the ease and success of prediction is then given 
by predicting more than 86 per cent, of the flora of Dublin from what is 
known of the distribution of plants in Great Britain ; and a further predic¬ 
tion that the floras of Dorset and Derby (apart from coast plants in the one, 
and highland in the other) will be much the same is borne out to the extent 
of 93 per cent, in Dorset and 97 per cent, in Derby. 
Finally, a correction is added to previous work upon the flora of 
Ceylon. Twenty-two species, formerly supposed endemics, have been found 
in Madras, and prove to be, as would be expected by Age and Area, on the 
whole decidedly on the ‘ Common' rather than the ‘ Rare ’ side in their 
Ceylon distribution. 
Literature Cited. 
1 . Colgan, N.: Flora of County Dublin, 1904. 
2. Guppy, H. B. : Homes of Family Names in Great Britain, 1890. 
3 . Matthews, J. R. : The Distribution of Plants in Perthshire in relation to Age and Area. Ann. 
Bot., xxxvi, p. 321, 1922. 
4 . Regan, C. Tate : The Freshwater Fishes of the British Islands, 1911. 
5 . Willis, J. C. : Studies of.. . Podostemaceae. Ann. R.B.G. Perad., i, p. 267, 1902. 
6. - : The Lack of Adaptation in the Podostemaceae. Proc. Roy. Soc., B. lxxxvii, 
p. 532, 1914. 
7 . - : Some Evidence against . . . Natural Selection. Ann. R.B.G. Perad., iv, p. 1, 
1907, and Further Evidence, p. 17. 
8. •—- : Sources . . . of New Zealand P'lora. Ann. Bot., xxxii, 191S. 
9 . - : Floras of Outlying Islands. Ibid., xxxiii, p. 479, 1919. 
10. -: Endemic Genera of Plants. Ibid., xxxv, p. 493, 1921. 
11 . : Age and Area, a Study in Geographical Distribution and Origin of Species. 
Cambridge, 1922. 
12. : Is the Theory of Natural Selection adequate ? Nineteenth Century and After, 
Oct. 1922, p. 615. 
and Yule, G. U. : Some Statistics of Evolution and Geographical Distribution in 
Plants and Animals, and their Significance. Nature, 109, p. 177, 1922. 
13. 
