80 THE PLANT WORLD 



related Asiatic form, the seedling has been found to be peculiar in that 

 the cotyledons, if they are really two in number, are united into a long 

 tube, through the side of which the plumule finally breaks in germina- 

 tion, and as Professor Campbell has pointed out, the two opposite lobes 

 of the first leaf suggest the possibility that the two cotyledons may be 

 really only one. 



Observations of great interest have recently been published by an 

 English botanist. Miss Sargant, who has investigated the anatomy of 

 monocotyledonous seedlings, especiallj' liliaceous forms, and has ad- 

 vanced a theory of the origin of Monocotyledons from Dicotyledons. In 

 studying the arrangement of the vascular system in the seedlings of a 

 large number of Liliaceae, she finally found a type of arrangement 

 which she considered the primitive one, that is to say the type from 

 which the others seem to be derived. This type, best represented in the 

 seedling of Anemorrhena, with which the more modified forms are con- 

 nected by intermediate stages, was found to be truly symmetrical 

 throughout, two massive bundles occurring in the cotyledon and sug- 

 gesting its origin by the fusing of two distinct cotyledons, each furnish- 

 ing one of the bundles, in some remote ancestor. 



Tile significance of this was first clearly seen when a comparison was 

 made with certain plants commonly regarded as Dicotyledons, particu- 

 larly some Ranunculaceae, and especially Eranthis, which has a seedling 

 which in appearance and internal anatomy, arrangement of the vascular 

 system, is remarkably similar to that of Anemorrhena. The single coty- 

 ledon of this member of the dicotyledonous Ranunculaceae is clearly 

 found by the lateral fusion of the two original cotyledons, and the sug- 

 gestion comes with considerable force that the more characteristic mono- 

 cotyledonous condition in a representative of the Liliaceae may have 

 been derived from a dicotyledonous ancestor, and the suggestion has a 

 very especial interest when it is remembered that the vascular arrange- 

 ment in this form is the one from which the others seem to have been 

 derived. 



A considerable number of plants regarded as Dicotyledons have 

 seedlings with but one cotyledon, in which case one is considered abor- 

 tive or the two cotyledons are grown together along one edge. In other 

 cases the fusion occurs along both edges, as is the case in Podophyllum, 

 forming a tube in which the plumule is contained a long time. Nearly all 

 of these forms have certain other characteristics in common and seem to 

 be adapted to life under certain conditions, but the evidence which they 

 offer in support of the theory recently proposed can not be considered 

 here. 



The simplicity of structure exhibited by the Monocotyledons as com- 

 pared with the Dicotyledons is very apparent. There is a quite general 



