4<;-_' 0. /<'. Wieland — Williamsonian Tribe. 



To the above list could of course be added by searching care- 

 fully through paleobotanic literature, various more or less sng- 

 gestive problematica. Bui now confining ourselves to the 

 hotter known forms, it is at once seen that the specific range of 

 staminate forms is fully as great as that of the ovulate cones 

 in the Yorkshire coast locality, the only one at all carefully 

 studied ; while the generic range is actually greater, since the 

 groups A, B, C and I) may finally prove to represent families. 



A first all-important fact indicating a great specific, generic, 

 and finally family variation, is that in these dozen fruits we 

 pass from flowers of large size with large frondlike microspo- 



Fig. 18. 



Fig. 18. Williamsonia sp. x 2. Study of features of the east (positive) 

 of the original in Paris Museum Yates collection, No. 2406. The orienta- 

 tion is uncertain. Note paragraphs in brevier on opposite page. 



rophylls to small forms made up of scale and stamen-like fertile 

 organs in which disks are not known to be always present, 

 there even being a suggestion of emplacement in short whorls. 

 And secondly, variety of sex type is definitely proven. Con- 

 formably to (Jycadeoidea, the showy staminate collars of 



Williamsonia, now called Williamsonia bituberculata (25), 

 together with other Yorkshire coast and Indian forms (cf. fig. 

 18) evidently split off from the base of large ovulate cones like 

 those of W. gigas. So that both from analogy and actual 

 occurrence of fossil forms the presence of bisporangiate 



Wi lliamsonia flowers is reasonably certain. Though the unity 

 of the cones and staminate collars in particular species can not be 

 easily proven, as the forms are not only seen to be numerous, 

 but it is held probable that Nathorst's interpretation of William- 

 sonia Sjpectabilis and W. pecten as unisexual flowers of either a 

 monoecious or dioecious form is correct. Also the Oaxacan disk 



