[907] 



MONOCOTYLEDONS AND THE DICOTYLEDONS. 315 



gyninosperms and the monocotyledons in a clear and lucid manner. 

 Ethel Sargant^ from detailed macroscopic and microscopic studies 

 of a large number of seeds and seedlings describes the dicotyledon- 

 ous seedlings that show a well-marked cotyledonary tube, thus sug- 

 gesting the origin of monocotyledons from a dicotyledonous stock. 

 She gives a complete bibliography of the more important articles 

 that have recently appeared on the subject, mentioning the work 

 of Lyon on the embryogeny of Nelumbo and Holm on Podophyllum 

 peltatiim and Erigenia bulbosa. Harris^ in a short article gives a 

 brief, but useful, resume of the attitude of modern botanists on the 

 origin of monocotyledons from dicotyledons. Coulter and Cham- 

 berlain believe that the phylogeny of the angiosperms will always 

 remain a baffling problem. They believe that there is not sufficient 

 evidence of the rnonophyletic origin of monocotyledons and dicoty- 

 ledons as claimed by Jeffrey, Queva, Sargant and others. They 

 believe that the facts are strongly in favor of an independent origin 

 of both monocotyledons and dicotyledons. 



Having briefly reviewed the current theories concerning the 

 origin and taxonomy of the angiosperms, it falls to the lot of the 

 writer to describe the taxonomic charts which accompany this ac- 

 count. In the arrangement of the dicotyledonous and the mono- 

 cotyledonous families, the plan has been adopted of showing the 

 generally recognized affinities of the different groups, rather than 

 absolutely relying on the proven natural descent, or evolutionary 

 relationship. Wherever that descent has been established definitely 

 by botanical investigation, it has been incorporated in the accom- 

 panying charts. Absolute affinity is an extremely difficult matter 

 to determine in families of such widely diversified structure. It is 

 important, however, to have some phylogenetic scheme which will 

 picture in a diagrammatic way the supposed relationship of the 

 numerous plant families. Such diagrams, the author believes, will 

 greatly assist in the future investigation of the morphology, embry- 

 ology and phylogeny of the flowering plants. 



^ Sargant, Ethel, " Theory of the Origin of Monocotyledons founded on 

 the Structure of their Seedlings," Annals of Botany, XVII : 1-92, Jan., 1903. 



- Harris, J. Arthur, " Monocotyledons or Dicotyledons," The Plant 

 World, VI : 79, Apr., 1903. 



