138 BENNETTITES. 



of 35 mm. At the base a fractured surface reveals the existence 

 of a slightly convex receptacle, from which is given off a compact 

 cluster of long peduncles, each of which bears at its apex an 

 oval seed. The seed-bearing peduncles are surrounded by several 

 involucral bracts closely applied to the surface of the fruit. 

 Numerous thin lamellae occur in association with the seminiferous 

 peduncles ; to these Lignier applies the term interseminal scales. 

 The seeds are arranged side by side close to the upper surface 

 of the mass of peduncles and intersemiual scales ; the latter 

 passing between and beyond the seeds, and their swollen distal 

 ends forming a protective covering to the blunt hemispherical apex 

 of the fruit. In surface view, the upper part of the specimen 

 appears to be made up of a large number of small projecting 

 areas with polygonal bases and rounded summits. Here and 

 there the projections arrange themselves in the form of rosettes 

 round a small central cavity, marking the position of a seed. 



As in JBennettites Gibsonianus the fruit is covered by involucral 

 bracts, but we have the interesting suggestion of Lignier that 

 these were not simply linear acuminate in form, but that the 

 portion of the bracts preserved is merely the petiolar part of a 

 leaf structure of which the pinnate or flabellate lamina has been 

 detached. This inference is drawn from a detailed examination 

 of the vascular strands traversing each bract. After comparing 

 and contrasting Bennettitea with the Cycadacece and Conifers, 

 Lignier concludes that they represent "a family which has been 

 derived with the cycads from common ancestors, but not from the 

 cycads themselves. Of these common ancestors the two families 

 have preserved the form of the trunk, the structure of certain 

 tissues, the foliar origin of the ovule, etc. But whilst the cycads 

 have retained a grouping of carpophylls on a single axis, and 

 have acquired special characters, such as the complication of the 

 leaf-trace and the lateral position of the ovules, the Bennettitece 

 have retained the simple leaf- trace and have acquired a terminal 

 position of the ovules, the reduction of the fertile axes to single 

 carpophylls, the grouping of these fertile reduced axes, and the 

 modification of the neighbouring leaves." l 



In a recent paper on fossil cycadean trunks from North 



1 Lignier, loc. cit. p. 73. 



