1917] CURRENT LITERATURE . 263 
It is safe to predict that the new journal will be of increasing interest 
to all botanists, and more particularly so to ecologists who see in forestry the 
practical application of their more theoretical studies —Gro. D. FULLER. 
Endemism and the mutation theory.—WILLIS, in papers previously 
reviewed in this journal,” working upon the flora of Ceylon, has proposed the 
theory that relative endemism is determined by relative age, the youngest 
species being the endemics. RIDLEY’ points out that Wituis has based his 
arguments upon statistics gathered from herbarium specimens; and illustrates 
that such will not agree with field statistics, the commonest species sometimes 
being poorly represented in the herbarium. In connection with his theory 
Witus States that “very common” plants could not disappear without a 
i Rp 
common species have disappeared within a few years, due to parasites, the 
activities of ae and Eeavey: in climatic changes. Eoaae Gaines} a 
the Ceylon 1 
they could have been evolved recently. 
The remainder of the paper is a criticism of the mutation theory as used 
sea to explain the origin of the Ceyon flora. Rip_ey’s arguments and 
theory, or WILLIS’ application of it, the paper is unconvincing to the . 
reviewer.—MERLE C. CouLTER. 
‘icin eld amis “Fincoe® tx Accs 4 Mecca ew ot 
Norfolk and Suffolk Counties, England, where upon sandy soil with only 22.5 
dominated 
_ ovina and Agrostis vulgaris are the most abundant species. ‘The sterility lity of : o S 
rere desta that some has never been cultivated and much of the restonce 
o 
ides is. a. i . es Great Britain 
In the second of his Papers. the author finds that the chief factor in 
: ae 
