230 



[Vol. 9, 1922] 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



Explanation of Plate 



Fig. 29. 

 Fig. 30. 



31. 



32. 



Fig. 

 Fig. 



Fig. 33. 

 Fig. 34. 



PLATE 18 



Isoetes echinospora Dur. Megaspores. 



I. Brochoni Motel. & Vendr. Megaspores. 

 7. Braunii Dur. Megaspores. 

 /. truncata Clute. Megaspores. 



7. Eatoni Dodge. 



Megaspores. 



saccharata Engelm. 



Mega spores. 



Fig. 35. J. riparia Engelm. Megaspores. 



Fig. 36. J. riparia var. canadensis Engelm. Megaspores. 



Fig. 37. 7. Pringlci Vnderw. Megaspores. 



Fig. 38. 7. Flettii (Eaton) Pfeiffer. Megaspores. 



Fig. 39. I. lacustris L. Megaspores. 



Fig. 40. J. occidentalis Hend. Megaspores. 



