566 Ridley .—On Endemism and the Mutation Theory . 
of the sun’s rays after a rainfall, which burns the leaves. This hairiness 
is one system. The flowers are small and yellow ; the fruit is orange- 
coloured, sweet, and eatable. It is small, hardly an inch through, so that 
birds can easily swallow it, and so disperse the seeds. It is obvious that 
a tree habituated to live in thick tropical rain forests would not thrive in 
a xerophytic country like Ceylon, though should it get there possibly it might 
exist in the small wet area. D . Scortechinii is a tall jungle tree attaining a 
height of upwards of one hundred feet ; its flowers appear never to possess any 
petals, and it seems to be self-fertilized. Owing to its great height and 
comparative rareness of flowering I have not been able to make many obser- 
vations on it. Like meliosmaefolia it inhabits wet jungles, but being a lofty 
tree its coma of foliage gets a full supply of light, and probably by reason 
of its being exposed to wind its leaves are able to dry faster and are not 
liable to injury from rain and sun. The fruits are of the same size as those 
of meliosmaefolia , but are green, glabrous, and not sweet. They appear to 
be dispersed by rolling and possibly by squirrels, rats, or bats. The absence 
of colour shows that they are not intended for dispersal by birds. 
Now here we have four or five species in this one region, but the whole 
of their life stories are quite different, and they do not grow alongside each 
other as Dr. Willis says of the Ceylon species. Do the other two species 
in Ceylon grow in the same situation and surroundings as D. indica ? We 
have no evidence from him or from Dr. Trimen that they do. Dr. Trimen 
describes the fruit of D. retusa as 1-1^ in. through, and orange. This 
suggests at once that it is bird-dispersed. The fruit of D. dentata is small 
and apparently whitish green. Both these plants require careful study in 
the field before we can say anything more definite about them. In the 
genus Calophyllum he states, p. 13, that an endemic species, C. parviflorum, 
lives beside the almost cosmopolitan species of the eastern tropics, C. ino- 
phyllnm. The two are very much alike, but the latter has a globose fruit, the 
former an oblong, rostrate one. The latter lives in beach-forests, the former 
more inland (how then can they be living beside each other?). Now is it 
to be supposed that the shape of the fruit can have any effect upon the life 
of the species sufficient to account for its being evolved by a natural 
selection of infinitesimal variations, though it may be correlated with some 
internal character fitting it for life more inland ? 
I am met at once with a difficulty : I cannot find any species of Calo- 
phyllum named parviflorum except a species of Bojer’s from Mauritius, but 
I must take it that Dr. Willis refers to one of the other ten species recorded 
in Dr. Trimen’s Flora. It is probably C. Burmanni to which he refers, as it 
occurs in the low country near the sea and has more or less oblong fruit, 
though that species differs from C. inophyllum in almost every other part of 
the plant, including the flowers, for it is apetalous. Indeed there is no species 
in Ceylon which really resembles C. inophyllum except in general character. 
