192 D- H. Scott. 



need not be described in further detail (see Williamson and 

 Scott, 1895). 



Fig. 20. Double bundle from the leaf -stalk of a uecent Cycad, to compare with 

 Fig. 19. sc. stone-cell. Other lettering as in Fig. 19. X 95. 



In its usual mature condition the structure is thus on the whole 

 of a Cj'cadean type; in the fortunate cases, however, where a young 

 stem, before secondary growth had begun, has come nnder observa- 

 tion, the resemblance to the stem of an Osmundaceous Fern is very 

 striking. 



When we come to the foliage we find that Fern-characters al- 

 together predominate. The petioles have often been found in connec- 

 tion with the stem, on which thej' are usually arranged in a 2/5 

 phyllotaxis. The foliar bundles, on entering the petiole, become more 

 or less fused, and assume a concentric structure, which they maintain 

 throughout the rachis (see Fig. 21), becoming collateral again in the 

 leaflets. The highly compound foliage has long been recognized as 

 identical with that of Sphenopteris Höninghausi, a fact which Mr. K i d - 

 s ton has recent!}' demonstrated by a detailed comparison.') The main 

 rachis forked at some little distance from the base, a character which 

 is shown in structural specimens as well as in impressions. 



The branching of the stem, first demonstrated by Mr. L o m a x in 

 1902 -), was very abundant in some specimens, and appears to have 



1) Kid s ton. The Microsporangia of the Pteridosperms , Phil. Trans. Royal 

 Soc, 1906. 



^) J. L m a X , Some new Features in Eelation to Lyginodendron Oldhamium 

 Ann. of Bot.. Vol. 16, 1902. 



