108 JOHN H. SCHAFFNER Vol. XXII, No. 4 



17. Bisporangiate sporophytes with the entire sporophylls 

 more or less differentiated and with but one kind of sporangia, 

 but the sporophylls arising side by side from a common stem 

 tissue. The typical state of the higher plants. 



Examples: Selaginella, Bennettitites, Magnolia, Aquilegia, 

 Lilium, Cypripedium, Lactuca. 



18. Monecious sporophytes in which the entire floral axis 

 with its parts is differentiated, the staminate and carpellate 

 flowers commingled more or less closely and showing large 

 vestiges of the opposite set of organs. 



Examples: Cocos, Aesculus. 



Note: The suppression of the opposite set of sporophylls is 

 of every degree, from this stage on, and has no relation to the 

 area of tissue involved in the sexual differentiation. There are 

 species in which the axis of the inflorescence is at first neutral 

 and gives rise to bisporangiate flowers below and then changes 

 above to a condition leading to the male state when only 

 staminate flowers are produced. 



Example: Lophotocarpus calycinus. Such species have an 

 intermediate position between stages 17 and 18. 



19. Monecious sporophytes having the axis of the inflo- 

 rescence differentiated, the staminate flowers being developed 

 first and, by a reversal of the sexual state, the carpellate later, 

 or more commonly the carpellate flowers first and the staminate 

 later. 



Examples: Cymophyllus fraseri, Carex nardina, Tripsacum 

 dactyloides, Zizania aquatica, Ricinus communis, Musa sapi- 

 entum, Stillingia sylvatica. Typha latifolia. 



In such inflorescences bisporangiate or abnormal flowers 

 frequently appear on the neutral transition zone where the 

 sexual state changes from one condition to the other. 



20. Monecious sporophytes having an entire branch or 

 inflorescence determined as staminate or carpellate. 



Examples: Carex lupulina, Euchlsena mexicana, Zea mays 

 (normal form). 



21. The lower type of diecious sporophytes having only a 

 moderate reduction in the size of the opposite sporophylls in the 

 monosporangiate flowers, with frequent reversals to the oppo- 

 site sexual condition — staminate plants developing carpellate 

 flowers and carpellate plants staminate flowers. 



