368 MR. AETHUE JOHN MASLEN ON THE 



cortex is wide, and there is a comparatively thick covering of parenchyma around the 

 woody cylinder. It seems certain that the phloem was very much better developed than 

 in Lepidostrobus ^t^ownii, Schimp. There is no evidence whatever in the latter species 

 of a thick parenchymatous sheath around the xylem. The better development of the 

 phloem in Z. oldhamms is also shown by a comparison of the leaf-trace bundles as seen 

 in transverse section in the middle cortex. In L. Broionii the phloem space is much 

 smaller than the corresponding space in L. oldhamms. 



PL XXXVII. fig. 23, i.e. shows the resistant band of inner cortex in L. oldhamms (/3). 

 It is seen to consist of about 6 or 7 radial rows of cells. It is thicker than in the a form, 

 but the leaf -trace bundles traverse it, and each receives a sheath from it exactly as has 

 been described. 



Here again there are differences as compared with Z. Broimii as described by 

 Prof. Bower. Immediately outside the endodermis (in Z. Zroivnii) there is a par- 

 enchymatous tissue with sclerenchymatous elements, which may be scattered singly 

 or, as the outer part is reached, may preponderate and form a dense mass of tissue *. 

 There is nothing in Z. oldhamiiis to correspond with this. 



Passing to the outer cortex, it will be seen to consist of a sclerenchymatous tissue. 

 PL XXXVIII. fig. 26 exhibits some of the cells in longitudinal section. They have thick 

 walls and an average diameter of about "02 to '03 millim. Many of these cells exhibit 

 beautifully the cross striation of the thickened cell-wall so characteristic of some 

 sclerenchymatous fibres (PL XXXVIII. fig. 27). 



As can be seen from the drawing showing the outer cortex and proximal end of 

 the pedicel (PL XXXVIII. fig. 28), and as can also be seen in transverse sections (see 

 Williamson, " Organization," Part XIX. fig. 58), the outer cortex passes outward into, 

 and forms the cortex of, the proximal end of the sporophylL Moreover, it is mainly the 

 cells passing up from below, accompanying the vascular bundle, which pass thus into the 

 pedicel ; the cells coming down from above appear to end abruptly against the outgoing 

 tissue. 



The outer cortex of this form differs from that of Z. oldhamiiis (a) in (1) the 

 general greater length and smaller diameter of the cells in the former type, in which all 

 the cells are distinctly fibrous, whereas in the latter most of the cells are not much longer 

 than wide ; and (2) in the |3 form the cells do not exhibit the peculiar preservation of 

 (apparently) cell-contents characteristic of Z. oldhamiiis (a). (Cf. PL XXXVI. fig. 8 & 

 PL XXXVIII. fig. 26.) 



The cortex of Z. Brownii difiers from that of Z. oldhamius not only iu the features 

 already mentioned, but also in the relative thickness of the three zones into which it is 

 divided. It will readily be seen by comparison of Bower's figure, pi. xvi. fig. 1, and my 

 PL XXXVI. fig. 1, that in L. Broimiii the inner and outer cortical zones are both thicker, 

 while the middle cortical space is evidently narrower. 



The Zeaf -trace Bundles and Sporophylls. — As already mentioned, these sections are 

 specially valuable on account of the good preservation of the sporophylls and sporangia, 



* Eower, in Ann. liot. vol. vii. p. 336. 



