142 SEVENTEENTH REPORT. 



THE ORIGIN OF THE AXTHOPHYTA. 



BY ERNST A. BESSEY. 



This paper does not represent to anv great degree the results 

 of the writer's own investigations but aims to bring together the 

 conclusions of the more recent investigations in this field, e. g. C. 

 E. Bessey^, Arber and Parkin, Wieland, Coulter and Chamberlain, 

 Hallier, Lotsy, Sargent, Eames, Henslow, Bancroft, Sinuott and 

 Bailey, etc. 



As here used the name Anthophyta is applied to that immense 

 group of seed-bearing plants which possess closed ovaries and true, 

 although often much simplified, flowers; in other words, the group 

 generally known by the name Angiospermae. At the time that it 

 was thought that all seed-producing plants were monophyletic the 

 name Spermatophyta was justified, with its subdivisions Gymno- 

 spermae and Angios]>ermae. The developments of recent years, how- 

 ever, have shown that the seed habit has appeared at a number of dif- 

 ferent points in groups but distantly related, e. g. Lycopods (al- 

 most, if not quite). Ferns, etc., and further, the cleavage between 

 the Angiospermae and the several divergent groups of the Gyrano- 

 sperms was so early and fundamental that it seems better to place 

 the flowering plants in a separate phylum, distinct from the several 

 other phyla of seed-plants.^ 



In spite of the frequent suggestions to the effect that the Antho- 

 phyta are polyphyletic in oi"igin (e. g. Coulter and Chamberlain^, 

 Kubart^) the two groups ^fonocotyledoneae and Dicotyledoneae 

 have too much in common to permit these suggestions to be adopted. 

 Thus we observe the complete identity of floral structures (leaving 

 out the much, reduced forms) such as calyx, corolla, stamens, car- 

 pels, ovules; of the methods of pollination; of the development of 

 micro- and megagametophytes (embryo-sac) and endosperm; of 

 fertilization (''double fertilization") ; of early embryonic develop- 

 ment and nourishment; of seed dissemination; as well as of vege- 

 tative structure in general. It is true that many differences occur, 

 but almost everv character that we ordinarilv call monocotyledonous 



1. For thfi titles of tlio inoro important papers on this sulijoot. tlio reader Is re- 

 ferred to the appended liiMiofrrapli v. 



2. nessey. C. K. A S.vno|)sis of Plant Phyla, p. r.2. 1907. 



.^. roulter and Chaniberlain. Morphology of Anpiosperins. Chapt. XV. 1003. 

 4. Kuhart. B. Bemerkuug:en zur P^seudanthlen- und Strobilustheorle. 1914. 



