284 Seaton : Embryo-sac of Nymphaea advena 



paper on morphological peculiarities of Nymphaeaceae and Helo- 

 biae, agreed with Lyon and Cook as to the monocotyledonous 

 embryo and vascular bundles, and went farther in saying that he 

 found even the flower could be made to fit into the monocotyle- 

 donous scheme. The six sepals of Nymphaea advena could be con- 

 sidered a perianth typically trimerous with three sepals and three 

 petals. Even in Castalia odorata, said to have four sepals, the 

 sepals are normally three in a cycle, but sometimes there is an ex- 

 pansion of the receptacle causing one sepal of the second cycle to 

 be brought outside. Schaffner maintains that many superficial 

 characteristics of secondary importance, such as similarity to Helo- 

 biae in habitat, rhizome habit, leaf forms, and number and arrange- 

 ment of ovules in ovularies, add strength to the monocotyledon- 

 ous idea. The embryo of Castalia odorata which Conard finds 

 "to have two cotyledons fronTthe first/' Schaffner, by dissecting 

 out very young embryos, found to show a resemblance to Nelumbo 

 and Nymphaea that could much less easily be seen in serial sec- 

 tions. Schaffner concludes his paper with the prediction that w 

 our increasing knowledge of the embryogeny of angiosperms we 

 shall be inclined to divide them into a number of parallel groups 

 rather than maintain the two of our present classification, dicotyle- 

 dons and monocotyledons. Perhaps a similar idea is expressed 1 

 another form by Mottier who calls the Nymphaeaceae anomalous 

 dicotyledons. 



Since Cook's paper on embryogeny was based upon the first 

 stages of the development from Castalia odorata material, and the 

 later stages from Nyniphaea advena, I give my own study of the 

 development of the embryo-sac, based altogether on abundant 

 material of Nymphaea advena in all the stages. 



The embryo-sac of Nymphaea advena 

 The material was collected at Ithaca, N. Y., and Cleveland, 





ith 



m 



Ohio. Twice in J 



for three con 



~- ...~. . ..._v. ... j Ktij f ajiu again iivilc ill n.uguoi, iwi *••■ — 



secutive summers, buds and flowers of various ages were collected 

 in the bayous of Fall Creek and in the Inlet of Cayuga Lake at 

 Ithaca. In September, at the same place, several plants were 

 uprooted and from the crown small young buds, formed for the 

 next season, were obtained. As these proved to be too young to 



ft 



