94 CYCADEAE, MEDULLOSEAE. 



is correct, and the figured specimen certainly favours it l , then Krannera 

 cannot be classed immediately with Cycadeae. The certain determination 

 of its^affinities must in any case depend on the discovery of fresh speci- 

 mens. Lastly Velenovsky takes some globular casts, which show the 

 place where a stalk has been broken off from them on one side, for the 

 seeds of Krannera, solely because they were found with it. The only 

 Cycad, as far as I know, in which the stem with the leaves attached can 

 be determined with certainty, is Zamites gigas, Morr. The specimen of 

 this plant came from the Upper Jurassic sandstone of Yorkshire, and was 

 obtained from its owner James Yates for the Paris Museum, where I saw 

 it. A figure of it is given by Saporta 2 . The stem bears a lateral bud 

 enveloped in handsome leaves ; in this respect and in habit also it recalls 

 Stangeria. It appears also to have been quite naked, though Saporta 

 contends that he has discovered traces of scales and places it among his 

 Cylindropodia. It has been already mentioned that English authors 

 consider the peculiar flowers known as Williamsonia, Carr. to belong to 

 Zamites gigas. Williamson 3 mentions a second similar but less perfect 

 specimen. He would also place in this species the stems covered all round 

 with leaf-scales which he found near Scarborough ; but from a specimen 

 which I saw in Oxford I should say that they are the stems of Ferns. 

 The specimens it is true lie on the same slab with several leaves of Zamites, 

 but no conclusion can be drawn from this circumstance. 



Carruthers 4 has described a very remarkable stem covered with 

 fructifications by the name of Bennettites Gibsonianus (Fig. 5). It is sili- 

 cified, and in a wonderful state of preservation, and comes from the 

 Lower Greenland of the Isle of Wight. Carruthers shows first of 

 all that all the remains known as Bennettites have a distinctly elliptical 

 and not a circular cross section, though they have not been subjected to 

 any particular pressure. The pith, which has no cauline bundle-system, 

 is surrounded by a simple secondary woody ring of great thickness, which 

 is divided by numerous tolerably broad medullary rays into portions of 

 unequal size. The rather narrow rind is enclosed in a compact armour 

 of leaf-bases in the same manner as in Clathropodia and Cylindropodia. 

 At the same time there are considerable intervals between the separate 

 members, and these are filled up with a thick mass of hair-formations 

 resembling paleae. The fusiform transverse sections of these paleaceous 

 scales r> show one or two cell-layers lying one above the other. The leaf- 

 bases themselves are rhombic in form on the cross section and contain 

 numerous vascular bundles in the neighbourhood of the periphery, which 



1 Schmalhausen (1), t. 4, f. 4. * de Saporta (4), vol. ii, t. 81. 3 Williamson (3), p. 665. 



4 Carruthers (1). '' Carruthers (4), t. 60, f. u. 



