G. H. Wieland — American Fossil Cycads. 425 



(Bennettites) Gibsonianus and Morierei. See figure 1. Plates 

 III and IY, given in Part I of these studies, may also be 

 referred to. 



In the inflorescence first studied there is, as was then men- 

 tioned, a large slightly conical central cavity with much chal- 

 cedonized borders covered by a druse of quartz crystals, 

 beneath which in just one small area about a millimeter in 

 length and inside the innermost synangia, there was originally 

 noticed a slight palisading which was at the time regarded as 

 simply an accident of silicification. But as verified over and 

 over since from material in the most wonderful degree of 

 preservation and beautiful differentiation of tissues by a natural 

 iron staining, this small area indicated a notable fact had we 

 known how to interpret it. The central axis, or receptacle, 

 bearing the fertile fronds with their petioles folded back once 

 adaxially, terminates as a much elongated conical, and prob- 

 ably in most if not in all cases abortive, ovulate axis. This 

 central and apical structure is preserved in several instances in 

 such perfection of essential parts and bundle systems that not- 

 withstanding its young and undeveloped condition, and the 

 minuteness of its ovules, the most accurate comparisons can be 

 made between it and obviously functional ovulate strobili. 

 That these apical ovulate axes are of essentially the same 

 structure as the more rotund to distinctly globular and much 

 larger seed-bearing strobili borne on the same trunk in the 

 case of such species as Cycadeoidea dacotensis, Marshiana. 

 and some others, admits of no doubt. All the evidence in 

 favor of the absence in these latter of fugacious organs of 

 staminate character, and their solely feminine function, cannot 

 now be conveniently given. But it led the writer to announce 

 Cycadean Monoecism for the first time in this Journal for 

 August, 1899 (vide page 164). The evidence which I have 

 thus far been able to produce points well nigh indubitably in 

 the case of the species just mentioned to a monoecious condi- 

 tion, the pollen-bearing axis being in this case morphologically 

 but not functionally bisporangiate. The existence and impor- 

 tance of these bisporangiate axes was first announced by the 

 present writer in the Yale Scientific Monthly for March, 1900, 

 at which time somewhat extended study of them had already 

 been made. 



Before taking up the subject of what I here designate the 

 staminate fronds, several remarks concerning data now con- 

 sidered in part may be recorded. 



The presence on the same trunk of markedly different and 

 much larger ovulate strobili surrounded, so far as my sections 

 thus far completed show, by sterile^ bracts only, would indicate, 



