120 G. E. Wieland — Cycadeoidean Flower-bud Structure, 



variation in the size of the disks and the number of micro- 

 sporophylls composing them. 



In the flower type here to be considered, however, there is 

 an added interest not only because of the large amount of 

 reduction in the fertile segments both ovulate and micro- 

 sporangiate, but especially because of the great relative bulk of 

 the microsporophylls and their very peculiar form. This is, 

 moreover, of importance in enabling us to criticize previous 

 restorations where the apical region of the flowers is less com- 

 plete. Not only so, but the restorations given herewith are 

 suggestive of certain larger hypotheses as to the true nature of 

 both ovulate and microsporangiate floral structure of undenia- 

 ble significance which it will be of much interest to briefly 

 take up following the present preliminary descriptions. 



While preparing material for my volume on the structure 

 of the fossil Cycads (Carnegie Institution Publication 34) I 

 noted as a specimen of especial interest an upper portion of a 

 trunk of the Yale Collection numbered 549 + 550. A half 

 dozen or more medium-sized flower buds enveloped by large 

 bract groups, and the distinctly rhombic-shaped leaf scars of 

 lesser to small size, were the particular features which arrested 

 attention. In general, the characters suggested C. dacotensis, 

 to which species Professor Ward had indeed referred both 

 these trunk fragments which I later found to fit together as a 

 single large more or less apical segment of a trunk or perhaps 

 branch. But the lesser variations from C. dacotensis as usually 

 seen led me to cut a section from one of the flowers, which 

 although it proved to be indifferently conserved, indicated the 

 structureless outlines or casts to be new and distinct. It was 

 noted that the microsporophylls were very heavy and thick in 

 the upper part of the flower ; but as the single section cut so 

 lacked finer structural detail, little could be said about the 

 floral features ; while on examining several other of the axes, 

 exteriorly more promising, little further was learned of the 

 structures present. As is often the case in the fossil cycads, 

 petrifaction had resulted in the replacement of the original 

 tissue by silica in much too granular to quartzose a condition 

 for the clear preservation of histologic details. The further 

 study of this specimen was therefore deferred, and attention 

 was not again directed to it until much later, when the sections 

 shown in figures 1 and 4 were cut from an isolated flower bud 

 I had collected at Minnekahta in the Fall of 1902. This flower 

 bud has a complete summit and at once recalled the trunk 

 apex and section just mentioned. For so nearly alike are the 

 general features, and the type of conservation, that it is not 

 impossible that the isolated fruit really pertained to the two 

 larger trunk fragments, and escaped attention when they were 



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