412 A CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



bulbose or cormose habit; and (3) Glumiflorae, branching from the latter, with 

 reduced floral structure. Many monocot families were regarded as "climax" or- 

 ders, in the delimitation of which the nature of the inflorescence was esteemed 

 as more decisive than the position of the ovary. This system counters the de- 

 fects noted in the Besseyan scheme with regard to oversimplification of the major 

 groups, overemphasis on hypogyny verus perigyny-epigyny, and neglect of tropi- 

 cal families. The stress on the major dichotomy between predominantly herba- 

 ceous as against predominantly woody lines, and the resultant characterization 

 of certain orders as polyphyletic, are features which have worked against its 

 more general acceptance. It seems to be agreed, however, that Hutchinson's 

 proposed phylogenetic classification of monocotyledons is by far the best which 

 has been proposed. His interest in geographical distribution (with its implied 

 endorsement of the theory of continental drift), the full description of orders 

 and families, and the abundant illustrations make his volumes among the most 

 useful and stimulating reference books on systematic botany. 



In Defense of the Phylogenetic Point of View 



Although the theory of evolution completely revolutionized the underlying 

 philosophy of biological classification, it brought with it no new data, as Mason 

 (1950) emphasizes, so that the chief distinction between natural and phylo- 

 genetic classifications was the interpretation of morphological characters in 

 terms of assumed evolutionary trends by the latter (Thoday, 1939). The earlier 

 workers were sanguinely optimistic that comparative morphology, alone, would 

 provide a satisfactory basis for a truly phylogenetic arrangement of angio- 

 sperms (Hallier, Bessey; Crow, 1926; Schaffner, 1934). Thus Sargant declared 

 that, "the origin of Angiosperms is perhaps the most important problem which 

 botanical morphology has yet to solve" (1908, p. 121). Serological investiga- 

 tion, according to the claim of Mez and Ziegenspeck (1926), put phylogeny on 

 an experimental basis and fully confirmed morphologically established evolu- 

 tionary sequences. 



A strong reaction, however, soon set in, based primarily upon: (1) the visibly 

 major element of speculation embodied in all phylogenetic schemes (Lam, 1936; 

 W. W. Smith, 1936; Sprague, 1940; Turrill, 1942; Danser, 1950; Metcalfe and 

 Chalk, 1950) ; (2) the failure of the paleobotanical record to reveal the necessary 

 forms connecting discrete modern groups (Arber, 1925; Turrill, 1938; Swamy 

 and Bailey, 1949; Axelrod, 1952); (3) the inability of systematists to agree on 

 what characters or taxonomic groups are to be considered primitive and what 

 advanced or derived, and hence which morphological sequences are validly phy- 

 letic (Zimmermann, 1930; Bremekamp, 1931, 1939; Turrill, 1938, 1942); (4) the 

 improbability of major living groups having given rise to one another (J. Hut- 

 chinson, 1923-1924, 1929; Engler; Gunderson, 1939b; Sporne, 1948, 1949); (5) 

 the questioning of the principal canons of classical morphology established in 

 the pre-evolutionary period (Zimmermann, 1930; Thomas, 1932; Arber, 1933, 

 1937; Lam, 1936, 1948a, 1948b, 1950, 1952; Watson, 1943); (6) the apparent 

 conflict between phyletic seriations propounded upon different kinds of evidence 

 (Hayata, 1921, 1931; Turesson, 1930; Gilmour, 1940; J. S. Huxley, 1940; Wat- 

 son), and (7) the presumed sacrifice of a classification of maximum utility in 



