568 Ridley —On Endemism and the Mutation Theory . 
Dilleniaceae of the East as illustrating his mutation theory, which study is 
based, I imagine, on the first volume of Hooker s Flora of British India. 
He states that Tetracera laevis is found in Ceylon, Malabar, and in Java 
and Borneo. This species is closely allied to T, assa, and is peculiar to 
Ceylon and Malabar, and does not occur elsewhere so far as is known, the 
other localities quoted being erroneous. Delinia laevis , he says, has only 
been collected in Malacca. ‘ If we accept the theory of infinitesimal varia- 
tions we must either admit that D. sarmentosa was evolved near Malacca 
and afterwards spread enormously, while D. laevis has not spread, or else 
that there has been a vast amount of destruction, reducing D. laevis to one 
locality or destroying the other species that were evolved with it. It is, 
however, very nearly allied to D. sarmentosa . The small spread of D. laevis 
is easily accounted for on the mutation theory, for it may have been quite 
recently evolved, and not having a very efficient distribution mechanism 
would not travel very far except in a great length of time. 5 An examina- 
tion of the type specimen of Delima laevis in the Kew Herbarium shows 
that it is Tetracera borneensis , Miq., a well-known and not very rare species, 
which has no connexion with Delima sarmentosa at all. 
Of Wormia he writes (p. 72) : ‘ Wormia triquetra is confined to Ceylon ; 
it belongs to the sub-genus En- Wormia , to which also belong W. pulchella , 
Wo meliosmae folia, W. Scortechinii, and W. Kunstleri . All the last three 
may be supposed to have split off from W. pulchella! Now strange as it 
may appear, Wormia Scortechinii and W . Kunstleri are the same species, 
and with W. meliosmaefolia are not Wormias at all but Dillenias, and have 
no connexion with Wormia pulchella , a true Wormia . Further Wormia 
triquetra, from Dr. Trimen’s description and figure and specimens preserved 
at Kew, is also a Dillenia — D. dentata, Thunb. The two genera are 
distinguished by their fruit, those of Dillenia being indehiscent with no aril 
to the seeds ; those of Wormia opening out into a rose-shaped pink or 
white circle of carpels widely dehiscing and exhibiting the seeds invested by 
a scarlet aril. 
I confess I do not understand Dr. Williss interpretation of the simple 
facts of evolution of a species as generally understood by naturalists. He 
states that the idea that endemic species were evolved to suit local condi- 
tions is based largely upon Wallace. Who ever possessed such a curious 
idea ? Let us take some examples of endemics. Aphyllanthes monspeliensis 
is a liliaceous plant occurring in a limited area on the Mediterranean where 
it is distinctly endemic, a monotypic genus of the Sowerbieae section with 
no relations nearer than Australia. Helxine Solerolii , Req. (Urticaceae), is 
an endemic of Corsica and Sardinia and has no relations at all in this region. 
Dioscorea pyrenaica , Bub., is endemic to the Pyrenees and the only species 
of its genus in Europe. How could these plants be evolved to suit local 
conditions, unless they are the relics of floras of which the rest is extinct ? 
