Feb., 1903.] 



Ohio NatuiIalist. 



Agrostemma githago 



EXPIyANATION OF FIGURES. 



For the drawings a Leitz stand was used. For Figs. 6 to 7, a No. 6 Zeiss ocular and a 

 I-I2 Bausch and X,omb oil immersion, for Figs. 8 to 24, a No. 6 Zeiss ocular and a No. 7 

 Leitz objective. 



Fig 



I. 

 2. 

 3. 

 4- 

 5- 

 6. 



7- 



S-12. 



13- 

 14. 



15- 

 16. 



17- 

 18. 



19- 

 20. 



2i. 

 22. 



23- 



24- 

 25. 

 26. 



Two archesporial cells. 



Three " " in cross section (slightly oblique). 



Functional megaspore. 



Two-celled embryo sac and inner zone of nucellus. 



Four- " " 



Eight- " " inner zone of nucellus nearly absorbed. 



Series of embryos showing transverse division. 



Embryo showing first longitudinal division. 



second and third longitudinal divisions. 



fourth ^ " 



fifth 

 of five tiers of cells and suspensor. 



also endosperm. 

 Mass of endosperm in basal pockst of embryo sac. 

 Spherical embryo of five tiers of cells. 



" " showing origin of cotyledons (c). 



Ovule showing the two-celled embryo sac, the two zones of the nucellus, the 



radiating arrangement of the cells of the nucellus, the path to be followed 



by the puUen tube, and the two integuments. 

 Embryo sac enlarging at right angle to the long axis; e, egg and synergids ; a, 



antipodal: end, endosperm. 

 Embryo showing the differentiation into cotyledons, calyptrogen, dermatogen, 



periblem and plerome. 

 Diagram of mature embrj'O. 



