458 BENNETTITALES [CH. 



to take one example, is a complete flower there are certain diffi- 

 culties which are not easily explained: as Nathorst has shown, 

 in this type there is a short stalk, but in W. whitbiensis the base 

 of the funnel has no stalk and there is no interruption of the 

 stout lamina at the centre or any indication of a scar. Nathorst 

 compares the funnel-like region of W . whitbiensis to a kind of 

 cupule which became detached after flowering 1 . But a cupule 

 is supported on an axis and, though no scar is apparent on some 

 of the more complete specimens, it is obvious that the verticil 

 must have been supplied with vascular tissue from some axial 

 organ. This brings us to the consideration of a morphological 

 point which cannot be definitely answered. Nathorst has pre- 

 viously raised the question is it possible that the microsporo- 

 phylls were attached to the upper part of an ovulate strobilus; 

 were the flowers bisexual and epigynous? He believes the answer 

 to be in the negative. Reference has already been made to the 

 probable occurrence at the apex of the receptacle of Williamsonia 

 gigas of a funnel-like organ of the type described by Williamson 

 as 'carpellary disc 2 ,' a term under which Nathorst 3 believes 

 that Williamson included two different things, staminate discs 

 borne on separate, unisexual, flowers, and sterile organs called 

 by Lignier 4 the infundibuliform apparatus. The latter, it is 

 believed, were attached to the apex of an ovulate strobilus as 

 shown in fig. 548, comparable in position with the leaves at the 

 summit of an inflorescence of Ananas. A comparison of the 

 fossils regarded as infundibuliform appendages with some of the 

 microsporophy 11- verticils shows that they are identical in form, 

 the only difference being that on the former there are no synangia. 

 This fact can hardly be regarded as negative evidence fatal to 

 the morphological identity of these sterile and fertile organs. 

 The available evidence, though far from complete, is favourable 

 to the view that in some Williamsonia flowers, e.g. W. gigas, the 

 microsporophylls were produced at the apex of the axis in the 

 position shown in fig. 548. To cite a rough analogy, in Cyca- 

 deoidea the flower was hypogynous as in Erica; in Williamsonia 



1 Nathorst (09) p. 10. 



2 Williamson (70) PL LII. : see also Seward (00) B, PL vm. fig. 1. 



3 Nathorst (09) p. 12, fig. 2. 4 Lignier (03 2 ) p. 34. 



