140 Dr. F. 0. Bower on Earliest Known Land Flora [April 30 r 



the discussions of recent decades. It was the paucity of facts that 

 kept opinion in suspense, hovering between rival arguments rather 

 than settling on assured data. Looking back upon the history of 

 that branch of Botanical Science which is called Comparative Mor- 

 phology, there is only one period that can rival the years from 1913 

 to 1920 in point of positive advance. It is the period which led up 

 to the great generalisations of Hofmeister sixty years ago. In the 

 glories of that work Britain had no direct share, though it was carried 

 out at the very time when Lyell, Darwin, Wallace, Hooker, and 

 Huxley were laying the theoretical foundation which gave their real 

 significance to the discoveries then made by Hofmeister. In the words 

 of Sachs : " When Darwin's theory was given to the world . . . 

 the theory of Descent had only to accept what genetic morphology 

 had already brought to view." Science it is true is cosmopolitan, 

 and should always be held as such. But still we in Britain may feel 

 a legitimate satisfaction that in these recent discoveries, which have 

 transformed the problems of Morphology, the material, the observa- 

 tions, and the arguments based upon them are mainly of British 

 origin. The channel of publication of the results, so largely derived 

 by Scottish workers from Scottish material, has naturally been the 

 Transactions of the Royal Society of Edinburgh. 



\NoU. — The Figures 1-5 have been prepared from the original 

 photographs of Dr. Kidston, F.R.S. The use of these illustrations 

 is gratefully acknowledged. They are taken from the three 

 Memoirs " On Old Red Sandstone Plants showing Structure, from 

 the Rhynie Chert Bed, Aberdeenshire," by R. Kidston, LL.D. F.R.S., 

 and W. H. Lang, D.Sc. F.R.S., published in the Transactions of the 

 Royal Society of Edinburgh, Yol. XLI. Part 3 ; XLII. Part 3.] 



[F. 0. B.] 



