414 A CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



evidence from all available fields, in the conviction that this is onr best and only 

 guide to true relationship (Copeland, 1940; Sprague, 1940; Sporne; Mason, 

 1950; Bailey, 1949, 1951; Eames, 1951; Constance, 1951; Rollins, 1952). Swamy 

 and Bailey have cautioned us (1949, pp. 203-204) : 



Before attempting to arrange surviving angiosperms in phylogenetic series, it is 

 essential to obtain reliable evidence regarding salient trends of evolutionary specializa- 

 tion in the various organs and internal structures of these plants. Such evidence can be 

 acquired only by comprehensive and time-consuming investigations of the dicotyledons 

 and monocotyledons as a wliole. 



A quarter of a century ago H. M. Hall wrote (1928, pp. 4^5) : 



The adoption of phylogeny as the guiding principle in the classification of animals 

 and plants would seem naturally to follow the acceptance of the theory of evolution. . . . 

 But whether classed as a method or merely as an attitude of mind, it is essential that 

 the phylogenetic spirit furnish the background for every system of classification. 



This statement would appear to be equally valid today. 



Phylogenetic Indications From Systematic Data 



In a recent short note, arrestingly titled "Phylogeny of Flowering Plants: 

 Fact or Fiction?", Tutin makes this challenging statement (1952, p. 26) : 



In the ninety-two years since the publication of the "Origin of Species" a great deal 

 of argument but remarkably little fact has been produced about the relationships of the 

 Angiosperms. . . . Meanwhile, neither paleobotany, morphology, anatomy or cytology has 

 thrown any light on the origin of the Angiosperms or of any major group within the 

 Angiosperms which an unbiased observer can regard as unequivocal. Indeed, one may 

 go further and say that no more is known now about the origin of any major group of 

 plants than was known in 1859. 



The balance of the present paper will be devoted to attempting to find what 

 indications of phylogeny, if any, may be safely drawn from data now available 

 through a century of progress in a few selected botanical disciplines. Attention 

 will be restricted primarily to comparative morphology, anatomy, embryology, 

 and biochemistry. Evidence from cytology and genetics is intentionally omitted 

 because of limitations in space and time, the fact that it has received the bulk of 

 attention in recent years, that it is rarely applicable above the generic level, and 

 that it has already been so ably summarized recently, notably by Stebbins (1950) 

 and Clausen (1951). This reviewer has had an opportunity to express himself 

 in regard to a few aspects of the bearing of these fields upon taxonomy (Con- 

 stance, 1951, 1953). At the close of the paper, three classical problems of phy- 

 logeny and classification will be briefly considered in the light of information 

 drawn from the various fields. These problems are: (1) the primitive habit of 

 angiosperms; (2) the status of "the Amentiferae" and hence of the Englerian 

 sequence; and (3) the origin and rehitionships of the monocotyledons. 



In the preparation of this material, I have attempted to read as much as pos- 

 sible of the pertinent literature of the past few decades, starting with current 

 publications and working backward. In general, I have not attempted to go 

 beyond the twentieth century, in the belief that the morphological classics of 

 the previous century are widely known and generally available. It is lioped that 

 the bringing together of as complete a bibliography as possible on the supposed 



