THE AGE AND AREA LAW 445 



shrewdly by Sinnott (8), who gives statistics of the growth 

 form of the species (trees, shrubs, and herbs) of Ceylon and 

 Peninsular India, which prove that the woody forms, especially 

 trees, are much more abundant in the endemic than in the 

 non-endemic flora. He also cites similar circumstances in a 

 number of small islands and Australia. The predominance of 

 woody forms in insular endemic floras has been remarked upon 

 by all those who have dealt with the subject, but whether 

 this is due to these floras being ancient, as Sinnott and others 

 suggest, or whether it is due, in part at least, to some specific 

 effect of insularity, remains to be decided. It is more than 

 probable also that herbaceous species more frequently possess 

 greater powers of dispersal and would reach isolated areas 

 more readily than the arborescent species, thus raising the 

 percentage of herbaceous forms in the non-endemic flora, but 

 in no way invalidating the age and area law, which is applied 

 by Willis only to age within the given region. Another objec- 

 tion raised by Sinnott to the age and area law is that " it 

 necessarily implies a greater antiquity for the herbaceous than 

 for the woody vegetation of the earth." The age and area 

 law deals, however, only with age within the country, not 

 with absolute age except in the case of endemics. 



Sinnott, however, admits more than Willis maintains when 

 he says (8, pp. 214-15) that " there is doubtless much truth in 

 Willis's main contention that, other things being equal, the longer 

 a species lives, the wider the range it will cover. The chief 

 argument on which the hypothesis is based is the fact, which 

 in the face of the data presented cannot well be doubted, that 

 endemic types have comparatively narrow ranges and non- 

 endemic types comparatively wide ones." In fact, his point 

 of view is summed up in his concluding sentence (8, p. 215), 

 where, after mentioning one or two additions to the list of 

 " modifying causes " of the age and area law in relation to 

 endemism, he says, " The purpose of the present paper is to 

 point out certain of these complexities and to show that no 

 single hypothesis like that of ' age and area,' however valu- 

 able it may be in explaining certain facts, can be used as a 

 key to the whole problem." 



The hypothesis that endemics are as a rule recent receives 

 confirmation in a recent contribution by Taylor (19), who, after 

 an examination of the endemic flora of the vicinity of New 



