LEPIDODENDREAE. 231 



preserved. Binney l has figured fine transverse sections of his Haloniae, but 

 unfortunately they are not sufficiently magnified to show the behaviour of 

 the different traces which traverse the rind, and which run partly to the 

 leaves, partly to the scars where the lateral branches have separated from 

 the stem ; for the two are according to Williamson essentially different. 

 The foliar bundles arise normally on the outside of the wood-cylinder, but 

 without affecting its structure. The other and much stronger bundles 

 behave exactly like those which supply lateral branches in Lepidodendron 

 Harcourtii in the manner described above ; they originate in a division of 

 the central strand, in which a fissure-like gap appears above the point of 

 departure. I have seen the preparations in Williamson's collection, but they 

 have unfortunately never been figured. If the section does not happen to 

 hit on one of the very small fissures, as is often the case, then the central 

 strand is not distinguishable from the normal type of Harcourtii ; this 

 perhaps is the explanation of the absence of this peculiar character from 

 Binney's drawings. It was mentioned above that Renault 2 , combining 

 Dawes' and Binney's views in modified form with those of other authors, 

 pleads for the division of Haloniae, some of which he looks upon as rhi- 

 zomes, the others as aerial branches of Lepidodendreae. To make the 

 origin of this opinion intelligible it should be first observed, that the 

 majority of palaeophytologists regard the Stigmariae, which will have to be 

 considered further on, as the rooting organs both of Sigillariae and Lepido- 

 dendreae. But since these Stigmariae contain undeniable secondary wood, 

 and Renault, following Brongniart's views, cannot allow of any such forma- 

 tion in Archegoniatae, he is obliged to keep all Stigmariae for the Sigil- 

 larieae, and is then met by the difficulty, that there are no subterranean 

 organs left for the Lepidodendreae. He inclines therefore to see "their 

 rhizomes in Haloniae. And since this does not do for all their forms for 

 reasons which have been already noticed, he endeavours by help of the 

 difference which exists between Williamson's and Binney's descriptions to 

 separate them into two groups, and considers the specimens of the latter 

 author, who finds no difference in the bundles of the trace, to be rhizomes, 

 and those of Williamson with two kinds of traces, one of which originates 

 in the division of the axile strand, to be branches of the heads of the trees 

 to which they belong. That this is the true account of the process of 

 thought in Renault's mind, as it may be gathered from his various publica- 

 tions, is sufficiently attested by the following passage 3 : ' The separation of 

 the species of Halonia into two distinct groups, which we have noticed here 

 as a hypothesis serving to reconcile the anatomical results of different English 

 authors, is justified also by the examination of the figure given by Brongniart,' 

 &c. The figures cited appear to me to be merely casts of various states of 



1 Binney (1), III, tt. 16, 17. a Renault (2). 3 Renault ('2), vol. Hi, Introd. p. 22. 



