52 



NATUEAL HISTOEY BULLETIN 



Explanation of Plates 



The abbreviations employed in describing figvires are as follows: stg. 

 stigma; st, stamen; sp, spathe; p,_ petal, and s, sepal. 



Plate I 

 Fig. 1. Open staminate flower attached to plant. 

 Fig. 2. . Mature staminate flower enclosed within the spathe. 

 Fig. 3. Staminate flower emerging from spathe. 



Fig. 4. Detached and empty staminate flower floating on water with 

 elongated axis trailing. 



Plate II 



Fig. 5. Median longitudinal section through mature staminate flower of 



Elodea ioensis still enclosed by spathe. 

 Fig. 6. A similar section through staminate flower of Elodea canadensis 



Michx. at a stage of development corresponding to that shown 



in Fig. 5. 

 Fig. 7. Open flower of Elodea ioensis. 

 Fig. 8. Leaf of Elodea ioensis. 

 Fig. 9. Petal of staminate flower, Elodea ioensis. 

 Fig. 10. Sepal of staminate flower, Elodea ioensis. 



