As it was the examination of this fragment of stem which first put me on to the track of the new cone, it may be well shortly to describe its chief characteristics, reserving all details for a future paper.
The specimen, which is about 7 mm.: in diameter, bears the bases only of somewhat crowded leaves, the arrangement of which, though not quite clear, was most probably verticillate, with from nine to twelve leaves in a whorl, those of successive whorls being superposed. Each leaf-base consists of a superior and an inferior lobe, and each lobe is palmately subdivided into two or three segments.
The leaf-traces, which are single bundles where they leave the central cylinder, subdivide in both planes on their way through the cortex, to supply the lobes and segments of the leaf.
The central cylinder is polyarch, the strand of wood having from nine to twelve prominent angles, with phloem occupying the furrows between them. With the exception of the spiral protoxylem-elements at the angles, the tracheae have multiseriate bordered pits, thus differing conspicuously from the scalariform tracheae of the Lepidodendreae. The interior of the stele is occupied by tracheae intermingled with conjunctive parenchyma. There is a well-marked formation of secondary tissues by means of a normal cambium.*
The Strobilus
Mr. R. Kidston, E.Gr.S., kindly informed me that he had in his possession sections of a fossil cone from Burntisland having certain points in common with the Williamson specimen. On inspecting these sections with Mr. Kidston I was soon convinced that this undescribed cone really belonged to the same plant as the fragment of stem in the Williamson collection, and that the latter might well be the peduncle of the former. At the same time, I satisfied myself, and Mr. Kidston agreed with me, that the whole organisation of his cone is fundamentally different from that of any Lepidostrobus, the decisive point being that the new cone has compound branched sporo-
- The general structure of this axis, including the course of the bundles and the
subdivision of the bracts, is correctly described by Williamson, cit., p. 297. As regards the latter point, he says “peripherally the bark breaks up into main or primary bracts, which again subdivide, as in the transverse section, into secondary ones, demonstrating that each primary bract does not merely dichotomize, but subdivides, both horizontally and vertically, into a cluster of bracts—a condition corresponding with what T have already observed in the smaller strobili described.” These smaller strobili are those of the Burntisland , to which, by a strange coincidence, Williamson, loc. cit., p. 295, erroneously attributed the same character, as regards subdivision of the bracts, which actually exists in the new cone. The only explanation appears to be, that Williamson interpreted the structure of the Lepidostrobus in the light of that of the peduncle, which, as we shall see, really belonged to a totally different fructification.
