Feb., 1904.] 
Nymphaeacae and Helobiae. 
89 
during the life cycle must be taken into account, otherwise the 
result will be largely artificial. As intimated above, the writer, 
through paleontological studies, came to the conclusion a number 
of years ago that Monocotyls did not come from Dicotyls nor 
Dicotyls from Monocotyls ; that the Angiosperms do not represent 
two sharpl}’ defined classes, but that there are a number of lines 
of development from some common stock ; and that on this 
account there are frequent independent duplications of important 
characters in quite di.stinct .series of forms. According to the 
view's expres.sed above the relationship of the groups under dis- 
cu.ssion may' be represented as .show’ii in the diagram ( Text Fig. 2 ) . 
Since lists of the important literature have recently' beeii given 
in a number of papers, it is not necessary to add an extensive 
bibliography here. 
1. Lyon, H. L. Observations on the Embryogeny of Neluinbo. Minn. 
Bot. Studies 2 : 643-655. 1891. 
2. Cook, M. T. Development of the Embryo-sac and Embryo of Castalia 
odorata and Nymphaea advena. Bull. Torr. Bot. Club 24 : 21 1-220. 
1902. 
3. Conrad, H. S. Note on the Embryo of Nymphaea. Science 15 : 316. 
1902. 
4. Camprei.d, D. H. On the Affinities of Certain Anomalous Dicotyle- 
dones. Amer. Nat. 36 : 7-12. 1902. 
EXPLANATION OF PLATES V-VII. 
The diagrams represent typical flowers selected from a series of 
variable types and show the actual number and po.sition of the 
floral organs. The other figures were drawn w'ith the aid of an 
Abbe camera. 
PDATE V. 
Fig. I. Section of vascular bundle from the peduncle of Nelumbo lutea. 
Fig. 2. Diagram of flower of Alisma plantago. 
Fig. 3. Diagram of carpellate flower of Sagittaria rigida. 
Fig. 4. Diagram of staminate flower of Sagittaria rigida. 
Fig. 5. Diagram of carpellate flower of Sagittaria latifolia. 
Fig. 6. Diagram of staminate flower of Sagittaria latifolia. 
PLATE VI. 
Fig. 7. Diagram of flower of Cabomba carol iniana. 
F'ig. 8. Diagram of flower of Brasenia purpurea. 
F'ig. 9. Diagram of flower of Potamogeton natans. 
F'ig. 10. Diagram of flower of Nymphaea advena. 
F'ig. II. Diagram of flower of Castalia odorata. 
Fig. 12. Diagram of flower of Castalia tuberosa. 
F'ig. 13. Diagram of flower of Nelumbo lutea. 
PLATE VII. 
F'ig. 14. Young embryo of Nymphaea advena. 
F'ig. 15. The .same embryo as in Fig. 14, back view. 
Fig. 16. Young embryo of Castalia odorata. 
Fig. 17. Older embryo of Castalia odorata, upper side. 
Fig. 18. The same embryo as in Fig. 17, under side. 
F'ig. 19. Still further developed embryo of Castalia odorata, showing 
“ Dicotyl ” appearance. 
