552 Ridley.— On Endemism and the Mutation Theory . 
collector who happened to be in its neighbourhood would naturally collect 
specimens. 
In an extensive tropical area like that of Ceylon, to make a census of 
scientific value upon which one could safely base deductions, a very large 
staff of collectors and botanists would be required ; in fact, a botanical survey 
such as has been of late years commenced for India would have to be organized. 
The number of botanists mentioned in Dr. Trimen’s Flora is under twenty, 
and this includes several who only resided a year or two in the island, and 
practically only Hermann, Koenig, Champion, Gardner, Thwaites, and 
Trimen collected on anything like a large scale. Dr. Trimen did the best 
he could with what time and materials he had, but, as he says, his w r ork is 
incomplete. 
Dr. Willis (Ann. Bot., 1 . c., p. 22) states that ‘ A very small accident 
may kill out a species while at or below the stage represented in the Ceylon 
classification by VR, whilst it will need a geological submergence or some such 
accident to kill out one represented by VC’, and ‘There is no evidence 
whatever that any of the angiospermous species of the Ceylon flora are 
dying out, and from analogy we may imagine this to be generally true ’. 
I first visited Ceylon in the autumn of 1888 and stayed for a month at 
Peradeniya with Dr. Trimen. At that time Hedychium coronarium , L., and 
H. flavescens were conspicuously abundant all round Peradeniya and Kandy, 
and Dr. Trimen marks both of them VC in the Flora, vol. iv, p. 245. 
I visited Ceylon several times later in 1912 and 1913, and went to 
Peradeniya on these occasions ; but it was not till my last visit that I 
noticed that both species had entirely disappeared, and I asked Mr. Lyne, 
the Director of the Gardens, if he had seen them anywhere, and he was 
surprised to hear that they had ever been common, as he had not seen a plant 
at all in Ceylon. 
Here is a case in which a plant, which in 1888 was very common, in 
twenty-five years has become at least very rare, without any geological 
cataclysm to account for it. It is difficult to give any reason for its disap- 
pearance, as no observer at the time seems to have noticed it. But as an 
example of the way a common plant may at least become rare, I would 
mention some observations of mine on Lantana mixta in Singapore. When 
I first arrived in Singapore in 1888, this shrub was very abundant all over 
the waste ground in Singapore ; on my last visit there it had become com- 
paratively scarce — one had to look about the country for it. I found a plant 
in the edge of the wood by the roadside, and on examining it found that 
every one of the young fruits on the whole bush was perforated by a small 
green bug, and that all these fruits which had been sucked by the 
bug withered up and never came to maturity. Now as Lantana is widely 
dispersed by birds, which swallow the ripe seed and pass it unharmed, the 
occurrence of the bug and its attack on the young fruit consequently 
