1877.] 



President's Address. 



443 



as I was informed by the Professor, during a visit to the same museum, 

 his species and specimens have largely increased in number and propor- 

 tionately in value — that is, from the palseontological point of view ; and 

 the address which I have quoted gives a summary of the state of the whole 

 collection up to the present time. 



A few words on the magnificent collection of vegetable remains, Creta- 

 ceous and others, that have been studied and described by Mr. Leo 

 Lesquereux in various published Eeports of thell. S. Geological Survey, 

 and in separate works issued under its auspices, may be fitly spoken here. 

 It would be difficult to overrate the value of these contributions to fossil 

 Botany, which, in its present state of advancement, affords no results 

 comparable with those obtained from the animal kingdom for fixing the 

 limits of periods, tracing the direction of migrations and the areas of 

 distribution, or for following the devious paths of evolution. In the 

 whole range of the natural sciences no study is so difficult, and at the 

 same time so fruitless, if we regard the amount of results accepted by 

 botanists, as compared with the prodigious labour their acquisition 

 by palaeontologists has demanded. Of all the orders of fossil plants of 

 the formations referred to, the Gymnosperms alone have, as a rule, yielded 

 much trustworthy information ; and this is due to their texture, to the 

 peculiar character of their vegetative and reproductive organs, to the 

 frequent adhesion of these to the branchlets, to their gregarious habits, 

 to their wide distribution, and to their close affinity with existing species. 

 Of other orders and genera of plants, with the exception of a few with 

 well -characterized foliage, as the Palms, the identifications of a large pro- 

 portion hitherto published are not recognized as having much claim to 

 confidence by those who have the largest acquaintance with the varied 

 forms of the vegetative organs of plants. And if the identification 

 of the fossil leaves of one country is so hazardous, what must be the risk 

 of identifying the fossil leaves of one continent with those of another ? 

 a forlorn hope which has constantly to be resorted to. The result, in 

 the case of the North -American Cretaceous and Tertiary floras, has 

 been the discovery of certain well-ascertained plants, which would 

 appear to show that various prevalent existing American genera have 

 inhabited that continent from a very early period ; but that, along with 

 them, there existed types of European, Asiatic, and Australian genera, 

 temperate and tropical, that are no longer associated anywhere on the 

 globe in a state of nature. It is well, under such perplexing conditions, 

 that men of ability and unconquerable zeal (such as Heer, Saporta, and 

 Lesquereux) are to be found who will undertake to investigate them ; and 

 while thanking them cordially for what they have done, I would urge 

 upon them the importance of constant reference to large Herbaria, in 

 order to enable them fully to appreciate the variability of foliar organs, 

 and the deceptive nature of the characters they present. 



Though doubtless the most productive to science generally, Dr. Hayden's 



2i2 



