[Vol. 9, 1922] 

 232 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



EXPLANATION OF PLATE 



PLATE 19 



Fig. 41. Isoetes macrospora Dux. Megaspores. 



Fig. 42. /. macrospora f. hieroglypliica (Eaton) Pfeiffer. Megaspores. 



Fig. 43. I. TucTcermani A. Br. Megaspores. 



Fig. 44. 1. foveolata Eaton. Megaspores. 



Fig. 45. 1. Engelmanni A. Br. Megaspores. 



Fig. 46. /. Engelmanni A. Br. Megaspores with dust-like microspores in the 



background, showing relative size. 



Fig. 47. /. Engelmanni var. caroliniana Eaton. Megaspores. 



Fig. 48. /. azorica Dur. Megaspores. 



Fig. 49. I. Duriaei Bory. Megaspores. 



