21 



It may be objected that, in using such a small area, a very slender 

 weapon has been taken with which to attack a great conception, 

 splendidly worked out from many angles not touched on here. 

 The obvious retort would be that part of the argument used by 

 the authors of that conception is phytogeographic, and it is 

 solely phytogeographic evidence in our local region that leads 

 to the suspicion that endemism may not really be a criterion of 

 antiquity or of woodiness at all. Many endemics may possess 

 both these not necessarily related qualities, or only one of them, 

 but that either woodiness or antiquity have much to do with 

 endemism seems a very open question. 



An altogether different viewpoint is that of J. C. Willis, who 

 has argued that the endemic species in a flora are the most 

 recent, especially if they are very local and not widespread. He 

 would measure the antiquity of an endemic by its ability to 

 spread, and he has shown that in the flora of Ceylon those en- 

 demics are oldest which are the commonest, and that the most 

 recent are the endemics which have been found only once or 

 twice, or at a few localities. "On the average the commonness 

 of a species depends upon its age from the time of its arrival in, 

 or evolution in, the country. The commonness of any individual 

 species will, of course, also depend upon its degree of adaptation 

 to local conditions, and upon many things which can only be 

 regarded as chance, such as the sudden appearance of new factors, 

 like disease, etc., in the problem." Upon this conception all 

 species would start as endemics, very local in youth, becoming 

 more widespread in middle age, and in old age either ceasing to 

 be endemics because they become too widespread to be entitled 

 to that name, or else, through specific senility, disease, or other 

 cause, dying out altogether. 



Our local endemics are so well known that their distribution is 

 easily checked with these points in view. Ten of them are very 

 rare, having been found only in one or two localities. They are 

 as follows: 



Savastana Nashii Hypericum Bissellii 



Salix squamata Pyrola oxypetala 



Dentaria incisifolia Helianthus Dalyi 



