704 THE INITIATION OF STAMINAL ZYGOMORPHY. 



Fig. 26. A median longitudinal section — not quite radial^of a stamen of Staphylea pinnata L. The 

 anther is in the archesporiuni condition, and each longitudinal row of the filament consists of about 

 nine cells. x 48. 



Fig. 27. A median longitudinal section — not quite radial — of a stamen of Staphylea pinnata ]-. The 

 spore mother - cells are in the tetrad condition. Each row of filament ground - cells consists of about 

 eighteen cells. x 48. 



Fig. 28. Sect. I. A section through the lower portions of the united carpels and the stamens of a 

 liower-bud of Greyia Sutherlandii L. Diagrammatic. x 12. 



Fig. 29. Sect. II. A section taken a little higher in the same flower. The basal portions of two 

 anthers have been traversed. Diagrammatic. x 12. 



Fig. 30. Sect. III. A section still higher in the flower. Three anthers have been cut. Diagrammatic. 

 X 12. 



Fig. 31. Sect. IV. A similar section taken still higher. Six anthers have been cut. Diagrammatic, x 12. 



Fig. 32. Sect. V. A section of the same flower, immediately below the base of the style. Eight 

 anthers are represented. Diagrammatic. x 12. 



Fig. 33. Sect. VI. A section of the same flower, passing through the style. Nine anthers have been 

 traversed. Diagrammatic. x 12. 



Fig. 34. A median longitudinal section — not quite radial — of a stamen of Staphylea pinnata L. The 

 anther contains mature pollen-grains. Each longitudinal row of ground-cells of the filament consists of 

 about thirty- three cells, x 48. 



Fig. 35. A median longitudinal section — not quite radial — of a stamen of Staphylea pinnata L. The 

 mechanism of the anther-wall has been laid down. Each longitudinal row of ground-cells of the filament 

 consists of about fifty-eight cells. x 24. 



Fig. 36. Details of transverse section of anther-wall represented in fig. 35. 



Fig. 37. A median longitudinal section — almost radial — of a stamen of Staphylea pinnata L. The 

 longitudinal rows of ground-cells of the filament each consist of from about fifty-eight to sixty cells. x 24. 



