152 Mr Seward, Notes on the Binney Collection 



secretory zone s composed of large sac-like spaces and several 

 small cells associated with patches of a dark brown substance. 



Text-figure 5 illustrates more clearly the structure of the 

 secretory zone, s, as seen in longitudinal view; the long clear 

 spaces correspond to the circular or oval sacs shown in the trans- 

 verse sections, fig. 3, PI. III. and fig. 12, PL IV.; with these are 

 associated groups of short parenchymatous cells, which are more 

 or less disorganised. Part of the meristem band is represented 

 at a in Text-fig. 5, and at px we have some of the narrow peri- 

 pheral elements of the corona. 



In fig. 11, PL IV. a few of the elements composing the secretory 

 zone accompanying a leaf- trace are represented on a large scale ; 

 these have the form of long thin- walled cambiform cells, with 

 straight or slightly oblique transverse walls, containing patches of 

 secreted substance in their cavities ; the appearance of the tissues 

 suggests a comparison with the sieve-tubes of normal phloem, but 

 the general character of the secretory-zone tissues differs consider- 

 ably from that of ordinary phloem. 



3. Conclusion and Summary. 



Having described the several tissues shown in the five sections, 

 it remains to summarise the results and to draw attention to such 

 general morphological or physiological conclusions as are sug- 

 gested by the anatomical features illustrated by the Binney 

 specimens. As already pointed out, one of the sections (no. 3) was 

 cut from a stem which Dawes described to Binney as exhibiting 

 the external character of Halonia, the cone-bearing branch of a 

 Lepidophloios. There is no reason to doubt the accuracy of Dawes' 

 statement. The section in question does not show any trace of the 

 vascular strands, which, as we know from other Halonial specimens, 

 were given off from the stele to supply each strobilus borne by the 

 fruiting branch ; but the absence of these vascular strands may be 

 easily explained by the assumption that the section was cut at 

 a level which did not coincide with the position of the vascular 

 axis of the cone-bearing tubercle. Binney's section of the Halonial 

 branch (no. 3) exhibits precisely the same anatomical characters as 

 the sections referred by this author to Lepidodendron Harcourtii ; 

 the Sections 1 — 4 are anatomically identical and cannot reasonably 

 be referred to distinct species. The reasons which lead me to refer 

 Binney's sections to Lepidophloios fuliginosus are (i) the presence of 

 a well-preserved middle cortex, and (ii) the indications of secondary 

 thickening. The first character is probably not of primary im- 

 portance ; in the true L. Harcourtii no sign of secondary thickening 

 has hitherto been observed in stems of so small a diameter as those 

 which we are considering. While pointing to the identity of 



