

G. R. Wielcmd — American Fossil Cycads. 423 



Art. XXXY. — A Study of some American Fossil Cycads. 

 Part IV.* On the Microsporangiate Fructification of 

 Cycadeoidea^ ; by G. K. Wieland. 



In this Journal for March, 1899, the writer presented in a 

 preliminary manner the first definite knowledge of male fructi- 

 fication in the Bennettitacese.;}; This was done at some length, 

 although the materials then studied represented only the 

 beginnings of the great collections now available, while the 

 nature of the preservation in the examples first selected for 

 investigation somewhat obscured the characters of certain 

 structures of fundamental importance. But these studies 

 have now so far progressed that the writer feels that it is 

 necessary to return to this topic. Its final consideration is, 

 however, reserved for a monograph on the entire subject, at 

 present actively in course of preparation. 



In the contribution just mentioned, after describing the 

 principal parts present in the pollen-bearing fructification of 

 Cycadeoidea ingens Ward, the writer noted the archaic type 

 of the sori, and distinctly stated their Marattiaceous character, 

 together with the fact of the exceedingly clear additional testi- 

 mony which these hitherto unknown fructifications offered in 

 favor of the belief in the direct descent of the Cycads from 

 such tree ferns as the Marattacese. Moreover, in describing 

 the arrangement of the fundamental parts, the writer said : 



" With regard to the homologies of these structures several 

 facts are worthy of mention. The radial divisions occurring in 

 the summit (of the fructification) are found to persist for a con- 

 siderable distance downwards, and under the microscope are seen 

 to consist in two lignified layers a single cell in thickness. They 

 correspond to the twelve vertices of soral distribution mentioned 

 above, and their presence is against the idea that the soriferal 

 axis is derived from the fusion of the sporophylls of a male cone 

 like that, for instance, of Zamia integrifolia. Another and 

 much more tenable hypothesis is that the soriferal (sorus-bearing) 

 axis is a series of twelve fused leaves (or fronds) with their sorus- 

 bearing pinnules turned inioards." 



* Parts I-III of these studies appeared serially in this Journal for March, 

 April, and May. 1899. 



f It is deemed advisable to retain for the present the generic name Cycadeoidea 

 Buckland, although it is, of course, certain that if Bennettites is to stand, as it 

 probably must, there are well-marked American species of this genus. The 

 writer will defer proposing any changes of generic or other names until makiug 

 a final publication. 



X A Study of some American Fossil Cycads, Part T. The Male Flower of 

 Cycadeoidea, with Plates II-IV, pp. 219-226, Fourth Series, Vol. VII. 



