CHAPTER XI 



THE ORIGIN OF MONOCOTYLEDONS 



IT has been generally supposed, from their some- 

 what simpler character, that monocotyledons 

 preceded dicotyledons in the evolution of plants ; 

 but the negative evidence of the most modern 

 researches in paleontology lends no countenance 

 to this view. It would seem that the latest 

 discoveries of intermediate forms connecting 

 gymnosperms with cryptogams, and the pre- 

 valence of two cotyledons, indicate a probable line 

 of development into dicotyledonous angiosperms, 

 but no undoubted link has yet been found. 



On the other hand, simpler structures may 

 indicate degradations and not necessarily 

 primitive features, as shown in the last chapter ; 

 and such would seem to be the case with 

 monocotyledons. One of the earliest known 

 members of this class, if it be such, is a plant 

 called Protolemna, described by M. Saporta from 

 a deposit at Cereal in Portugal, of the later 

 Jurassic rocks. It appears to resemble our duck- 

 weeds (Lemna) in some respects, but is of a higher 

 type, possessing a stem or distinct axis bearing 



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