Nov., 1905.] Life History Sanguiiiaria canadensis. 383 



The above paper was prepared in the Department of Botany 

 of the Ohio State University as a minor for the degree of Master 

 of Arts. The work was done under the direction of Associate 

 Professor J. H. Schaffner, to whom the writer wishes to express 

 his sincere thanks for the kind assistance and suggestions, 

 without which the paper could not have been completed. 



DESCRIPTIONS OF PL.\TES. 



All drawings were outlined under a camera lucida with the 

 following optical combinations: 



Bausch and Lomb — 1 oc, if obj. — Fig. 1. 



Bausch and Lomb — 1 oc, ^ obj. — Figs. 20. 21. 



Bausch and Lomb — f oc, ^ obj. — Figs. 2-8, V.^, I.j-IT, 22, 2;j. 



Bausch and Lomb — 2 oc, ^V obj. — Figs. IS, 19. 



Leitz — 4 oc, 7 obj. — Fig. 10. 



Leitz — 6 oc, 7 obj. — Fig. 14. 



Zeiss — 18 oc, Leitz 7 obj. — Figs. 9, 12. 



Zeiss — 18 oc, Leitz 3 obj. — Fig. 11. 



Section of young ovulary, showing incipient ovules. Killed 



\rchesporial cell. Killed l()-(3-'()-l. 

 Megasporocyte with two parietal cells. Killed 12-9-'04. 

 Megasporocyte with three parietal cells. Killed ;:5-13-'05. 

 Megasporocyte with parietals divided. Killed .':}-l-'05. 

 First division of megasporocyte. Killed 3-i;i-'05. 

 Four megaspores and parietal cells. Killed 3-22-'0.5. 

 Four megaspores showing tetrad arrangement. Killed 



Eight celled embryo-sac Killed 3-28-'0.5. 



Embrvo-sac with oospore. Antipodals with two nuclei. 

 '04. 



Outline of ovule with oospore. Killed 4-10-'O4. 



Oospore with remains of synergids. Killed 4-16-'04. 



Two-celled embryo. Killed 5-12-'04. 



Three-celled embryo. Killed 5-16-'04. 



Young embryo showing eight cells in section. Killed 



Spherical embrycj with long suspensor. Killed 5-29-'04. 

 Degenerating antipodals. Killed .5-29-'04. 

 Embrvo showing large suspensor and cotvlcdons at the time 

 . Killed 6-6-' 04. 



Section of stamen with microsporocvtes and tapetal cells. 

 Killed 10-6-'05. 



Fig. 20. Section of microsporangium showing microsporocytes just 

 before formation of tetrads. Tapetal cells with two nuclei. Killed ll-9-'05 

 Fig. 21. Microspores with remains of tapetum. Killed 12-9-'05. 

 Fig. 22. Single microspore. Killed 12-9-'05. 

 Fig. 23. Pollen grain. Killed 3-22-'05. 



