148 



JOURNAL, R.A.S. (CEYLON.) 



[Vol. IX. 



200. Yet very nearly all belong to the same genera, which 

 are almost identical for both regions. It is thus possible 

 to make the contradictory assertions that the floras are 

 very similar and very different. 



Let us take some illustrative examples. Of the genus 

 Strobilantkes, consisting of the well-known " Nillus," the 

 Ceylon hills possess 22 peculiar species, and the Nilgiris, 

 &c, about 29, whilst only 2 are found in both regions ; of 

 the mountain species of Balsam, genus Impatiens, there are 

 also 2 species common to both ranges, whilst Ceylon has 

 10 others endemic, and the Nilgiris 30 ; and other examples 

 could be easily given. 



These representative species of one genus in different 

 areas were a great puzzle to naturalists until the deriva- 

 tive theory of the origin of species became generally 

 accepted, when it became evident that scientific "affinity" 

 really meant relationship by descent. If we suppose a 

 common origin for both these Hill-floras in the past, or 

 derive the Ceylon one from the Peninsular, the differences 

 now seen in the two districts indicate a sufficient lapse of 

 time since their separation to allow of the evolution under 

 different surroundings of new forms of the rank of species, 

 but not of the superior rank of genera. In the case in 

 question the energy with which this differentiation of 

 specific forms has gone on is highly remarkable. 



There are cases where the relationship of distinct floras 

 is less intimate still, where it is traceable only in the 

 larger groups (of genera) called Natural Orders. The two 

 richest and most specialized floras in the world, as already 

 noticed, are those of the Cape and Australia ; probably, 

 scarcely a single genus is common to them, yet the large 

 and well-marked Natural Orders Proteacece and Restiacece 

 are abundant in each of these far distant regions, and are 

 almost confined entirely to them. This, according to present 

 views, implies a common focus of origin in a remote past. 



7. To return to the Ceylon flora. Of our endemic species 

 the great mass, fully five-sixths,*' belong, as would be 



* The numbers given in this paragraph must not be regarded as more 

 than fairly close approximations. I am not able to make the investiga- 

 tions here which are necessary to ensure close accuracy. 



