98 ILLINOIS STATE ACADEMY OF SCIENCE 



Garden, and to Miss Gladys Gladfelter for helping me 

 to secure material difficult to obtain. Also to Dr. L. C. 

 Petry of Syracuse University for making the photograph 

 of the vascular structure of the cotyledonary plate. 



LITERATURE CITED. 



1. Conard, H. S., Notes on the embryo of the Nymphaceae. Science 



15: 316. 1902. 



2. Cook, M. F., Development of the embryo sac and embryo of Castalia 



odorata and Nymphea Adveba. Bull. Tor. Bot. Club 29: 211. 

 1902. 



3. Coulter, J. M., The origin of monocotyledony. Records of the 50th 



Anniversary of the Missouri Bot. Gardens, St. Louis, Mo. 



4. Coulter, J. M., and Land, W. J. G., The origin of monocotyledony. 



Bot. Gaz. 57: 509. 1914. 



5. Farrell, Margaret E., The ovary and embryo of Cyrtanthus sau- 



grineus. Bot. Gaz. 57: 428. 1914. 



6. Lyon, H. L., Embryo of Nelumbo. Minn. Bot. Studies 11: 643. 1901. 



7. York, H. H., Embryo sac and embryo of Nelumbo. Ohio Naturalist 



IV: 167. 1904. 



LEGENDS FOR FIGURES. 



Fig. 1. Seedlings which had germinated naturally, in the Illinois 

 River. 



Fig. 2. Micropylar end of young ovule. 



Fig. 3. Spherical proembryo from Fig. 2. Begins to show traces of 

 the traces of the formation of the root and cotyledons. 



Fig. 4. Older proembryo. 



Fig. 5. Photograph of a wax model of a young embryo with a single 

 cotyledon. 



Fig. 6. Photograph of a wax model of a slightly older embryo. The 

 first cotyledon is large and in the background; the second 

 cotyledon is small and is in the foreground. 



Fig. 7. Diagram giving the shape of an older embryo: c, cotyledon; 

 m, meristemic tip. 



Fig. 8. Diagram giving shape and relative size as compared with 

 Fig. 7, of an older embryo. 



Fig. 9. Diagram of the desmogen strands of a young seedling made 

 from serial longitudinal sections. Actual size of embryo. 

 Length of cotyledons 15 mm. Length of epicotyl 4 mm. 

 PR, primary root; vp, cotyledonary ring; L^L 3 , first, second 

 and third leaves; MT, meristematic tip; rs, root strands; 

 cps\ cps-, primary cotyledonary strands; st, stem traces; 

 ess 1 , ess 2 , secondary cotyledonary bundle traces; V, P, leaf 

 traces. 



Fig. 12. Photograph of a wax model made from serial transverse 

 sections of the cotyledonary plate of the same seedling. The 

 sections were 10 u thick. Four central bundles usually 

 termed "stem bundles" are seen. Surrounding these are 

 two concentric rows of bundles. The cotyledons were cut 

 off from the stem between the inner and outer peripheral 

 rows of bundles. The lattice work arrangement of the 

 vascular strands is evident. 



