372 BENNETTITALES [CH. 



cylinders; she also describes a new species, C. buzzardensis 1 

 (fig. 578), in which there are 3 8 or more cylinders. Neither 

 of these stems affords any evidence of the possession of fertile 

 shoots; they agree closely with stems of the Bucklandia type 

 in their comparatively slender habit and differ in this respect 

 from Buckland's Portland species. The occurrence of more than 

 one vascular cylinder in the stems Cycadeoidea (= Bucklandia) 

 Yatesii and C. (= Bucklandia) buzzardensis suggests the possibility 

 that this feature was characteristic of other species included 

 in Bucklandia. 



It is clear that some at least of the stems referred to the genus 

 Bucklandia bore flowers of the Williamsonia type 2 , and it is not 

 improbable that the stems described by Dr Stopes as Cycadeoidea 

 Yatesii and C. buzzardensis (fig. 578) possessed fertile shoots 

 comparable with those of the Middle Jurassic species W. gigas. 

 Dr Stopes' s contribution, while establishing a close agreement 

 in anatomical features between some Lower Cretaceous stems and 

 those of Cycas, does not warrant the further conclusion that these 

 stems were in other morphological characters closely allied to 

 modern Cycads. The main features of Cycadeoidea may be 

 summarised as follows: The principal trunk is generally un- 

 branched (fig. 507) and identical in habit with some species of 

 Macrozamia, Dioon, and Encephalartos (cf . figs. 379, 382) ; in 

 some species, e.g. Cycadeoidea Marshiana, C. superba 3 , C. nana*, 

 the plant is represented by several approximately equal, thick, 

 tuberous stems, in some cases easily separated from one another : 

 a similar clustered habit is exhibited by certain forms of Ence- 

 phalartos. The size of a Cycadeoidea trunk varies from a few 

 centimetres in length with a diameter of similar dimensions, as 

 in C. pumila, to over a metre long as in C. gigantea (fig. 535), 

 or as much as 3 4 metres in C. Jenneyana with a diameter of 

 about half a metre. The surface is covered with persistent leaf- 

 bases, exactly as in many recent Cycads, embedded in a thick 

 mass of ramental scales which often stand out as a prominent 

 reticulum, the petioles having partially decayed before the pene- 

 tration of the mineralising solution through their harder tissues 



1 Stopes (15) p. 309. 2 See page 425. 



3 Wieland (06) Pis. vi. xm. 4 Ibid. (12) p. 88, fig. 10. 



