760 ^ CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



Arealkunde (1943), which is in many respects a textbook of areography. More 

 recent is the great Dutch project of the Flora Malesiana (van Steenis, ed., 

 1948 — ), which, altliough in the main taxonomic, is so broadly based on geo- 

 graphical principles that it can scarcely fail to add enormously to our knowledge 

 of the distribution of plants in a particularly significant part of the world. There 

 are also numerous accounts of the phytogeography of sundry parts of the north- 

 ern temperate regions and to represent these there can be no better choice than 

 Hulten's beautifully produced Atlas (1950), which deals exhaustively with the 

 geography of the Scandinavian flora. Of very different scope is Willis' third and 

 largest book The Birth and Spread of Plants (1949) which, somewhat hidden by 

 a rather awkward kind of presentation, contains much of real importance. 



The war itself was responsible for not a little progress in the paths of plant 

 geography. The extension of hostilities into the great and relatively unfamiliar 

 spaces of the Pacific, especially, caused a considerable revision and augmentation 

 of our knowledge of those regions, in which the botanists took their fair share, 

 as is instanced by Merrill's useful and delightful account (1946) of tropical 

 vegetation in that area. 



But the over-all impression of these later years, and one indeed hopes that 

 it is a true estimate, is that there is coming about a much needed reintegration 

 of the different branches of plant geography. This may be illustrated by reference 

 to three points. First there is the growing tendency for purely taxonomic works, 

 such as floras and systematic monographs, to pay more attention to the geography 

 of their subjects, to bring together as much geographical information as they 

 are able to and often to illustrate it with maps. This is desirable enough in 

 itself, but it is also an enormous help to the phytogeographer, who must rely so 

 much on reliable taxonomy for the facts which he endeavors to interpret. Second, 

 one has only to look at recent volumes of the periodicals devoted to ecology to 

 see how much the horizons of the ecologists have widened and how much more 

 concerned with the main stream of plant geography they are becoming. Finally, 

 there is the development which, more than anything else perhaps, characterizes 

 the postwar years, namely, the growth of that combination of taxonomy, geogra- 

 phy, and genetics which has come to be known as cytogeography, itself so 

 essentially a synthetic effect. It is very apposite, in this volume which celebrates 

 the first hundred years of the California Academy of Sciences, to mention a 

 publication which best typifies this latest phase in the development of plant 

 geography, Babcock's great study of the genus Crepis, which appeared in 1947. 

 It is further work of this kind, based on phytogeographically significant plant 

 groups, that is more likely than almost anything else to speed the progress of 

 plant geography. 



At the end of the first century of the Academy's history, what are the chief 

 impressions 1 Two seem particularly noteworthy. One is the truth of the aphorism, 

 Plus ga change, plus c'est le meme chose. Probably no previous hundred years 

 has seen such profound changes as this latest century, certainly not in the scien- 

 tific world, and yet one cannot help feeling that, if Alphonse de Candolle and 

 some of the other pioneers of plant geography could once more walk the earth, 

 they would understand us and our problems pretty well, though we might for a 

 time speak in rather different dialects. Advance in knowledge since their time 

 has indeed been enormous, but it has been am])lification rather than violent 



