370 ME. AETHUE JOHN MASLEN ON THE 



however, the structure is quite similar : at c. is the sclerotic cortex, bounded externally by 

 a well-marked zone of smaller cells constituting an epidermis; at x., the xylem; p., the 

 phloem space ; i.c.sh., the remains of the inner cortical sheath ; and Pa., the parichnos 

 space. 



The attachment to the sporangium is shown to be quite narrow ; and passing up into 

 the cavity of the sporangium is a mass of parenchymatous tissue, 6, which, spreading 

 out laterally, occupies a considerable portion of the floor and w^alls of the cavity, being 

 thickest immediately above the line of insertion and gradually thinning-out laterally. At 

 sp.w. is the sporangial wall, consisting of a single layer of palisade-like cells. 



PL XXXYIII. fig. 33 is a longitudinal section through much the same region of the 

 pedicel as in the last figure, and we see here the same tissues. At h is the pad of paren- 

 chyma forming the floor of the sporangium ; as can be seen in fig. 32, it is continuous with 

 the cells forming the sheath Lc.sh. around the leaf-trace, near to which the cells become 

 more elongated in the direction of the length of the bundle, as shown in fig. 33. This 

 tissue invariably contains a number of characteristic cells with dark contents; some of 

 these cells are shown in figs. 32 and 33. 



At X. (fig. 33) is the xylem, consisting as usual of scalariform tracheae, below which the 

 rather abundant tissue j;., consisting of small elongated elements, appears to be the phloem. 

 Below this, again, come the large clear- looking cells of the inner cortical sheath, i.c.sh. 

 The parichnos space, JPa., is shown, as well as the sclerenchymatous elements of the 

 cortex, G. 



Reverting to PI. XXXVIII. fig. 28, w^hich shows the outer cortex and proximal end of 

 the sporophyll in nearly radial section, it will be seen that the sporangium shows the attach- 

 ment to the pedicel to within a short distance (1-6 millim.) of the axis of the cone. The 

 distal point of attachment can be seen in PI. XXXVIII. fig. 34, or better in my previously 

 given figure illustrating the position of the ligule *. It will be seen that this point is quite 

 close to the periphery of the cone, thus show^ing that the sporangium was attached to the 

 pedicel by almost the whole length of its base. But although the attachment was thus a 

 very long one, it was at the same time very narrow. 



Sir Joseph Hooker, in his classical paper on Lrpidostrobus f , gives a restored section 

 (which has been copied into most of the text-books) in which the sporangium is shown 

 attached to the pedicel only by a narrow neck of tissue near its outer end. In my figure 

 ('Annals of Botany,' loo. cit.) precisely the same appearance is presented. In the latter 

 case, however, it is due merely to the fact that, owing to the small tangential wadth of 

 the attachment, the section has traversed it only near its distal extremity; and the same 

 explanation, in all probability, can be applied to Hooker's sections, which I have 

 examined in the Jermyn-Street Museum. 



As Dr. Scott points out in his memoir on Spencer it es :—'' The attachment of the 

 sporangium, either by the whole length of its lower surface or by a considerable part of 

 it, to the upper side of the pedicel, appears to be constant in all species of Lepidostrobus 



* Maslen, " The Ligule in Lepidostrohus;' Ann. Jiot. vol. xii. p. 25?>. 



t " Remarks on the Structure and Affinities of some Lepidosirobi," Mem. Geol. Suxv. voL ii. part n. 1848. 



