DERIVATION OF THK FLORA AND FAUNA 359 



I shall (jiiotc at some length. They state that evidence for a more recent origin 

 of herbaceous plants is furnished by palaeontology, anatomy, phylogeny and phyto- 

 geograj)h)-. ICvidence from palaeobotany is, however, not conclusive, because herbs 

 are much less tit to be preserved as fossils, but it is true that they increase in 

 number in the younger formations. l^Lvidence from anatomy and phylogeny are 

 said to be [)ositive; within a group including both ligneous and herbaceous spe- 

 cies, the former show other primitive characters; of the Leguminosae the more 

 primitive members are all woody (Mimosaceae, Caesalpiniaceae), the proportion 

 of herbs being vastly greater among the Papilionaceae. The authors continue, p. 572 : 



It is f^^enerally admitted that endemic species of a flora . . . are for the most part 

 more ancient than the non-endemic element, for they must either have had their origin in 

 the region ... a process usually requiring a long time — or else they must be remnants 

 of an older vegetation which has elsewhere become extinct. Endemic genera and 

 finally endemic families are in this way regarded as progressively more ancient portions 

 of the flora. 



I doubt that this statement is of general application; we cannot argue that, 

 in a given flora, all endemics are more ancient than the wides, because a widely 

 distributed species may have remained unchanged for millions of years and be 

 older than another which, for various reasons, happens to have become greatly 

 restricted in range and endemic in a small area. WiLLlS and his school are dia- 

 metrically opposed to the opinion of SiNNOTT and Bailev and neither is in pos- 

 session of the absolute truth. 



Proceeding to an analysis of certain insular floras deserving special attention 

 the authors assume that, if woody types are more ancient than herbaceous, a 

 flora which has been for a long time isolated ought to contain a large proportion 

 of woody endemics, and this is what they do find. Their analysis of the Juan 

 Fernandez flora was based on Joiiow's work, but this has long been out of date 

 and the figures are incorrect (new ones will be found in Chapter IX). so I shall 

 leave this subject aside here. The general conclusions in the chapter "Discussion 

 of Isolated Insular Floras" deserve to be quoted in full (p. 579). 



It is thus very clear that woody plants constitute a more conspicuous element in 

 the flora of isolated oceanic islands than in the flora of adjacent continental areas from 

 which their vegetation has possibly been derived, and also that the most ancient por- 

 tion of the island floras, if endemism is to be regarded as a criterion of antiiiuity, is 

 much more woody than the recently acquired elements. Annual herbs, which seem to 

 be the last step in reduction, are almost entirely absent from insular floras, as has 

 been noted by Darwin, Hooker, and others. Since the vegetation of these isolated 

 oceanic islands is to be regarded as more ancient in its composition than that of larger 

 land areas, it may be looked upon as a vestige of an earlier and much more uni- 

 form flora which flourished over the earth during the middle or latter part of the Ter- 

 tiary, and before the great flood of herbaceous vegetation, developed chiefly in the 

 north temperate lands, had spread over the globe. This conclusion is strengthened by 

 the many similarities which these widely separated island floras bear to one another. 



Some of the statements made by these authors are questionable, but in the 

 main I agree; only I prefer to say "early to middle Tertiary". Darwin, who was 



