50 



FOSSIL PLANTS. 



Fig. 8 is a vertical section of the pedicel and apex of a scale or bract (magnified 

 four diameters) tolerably well preserved, together with part of the Sporangium which it 

 supported, not so well preserved. The structure and shape of the bract is like that 

 shown in Plate VII, fig. 8 ; but of the original form of the Sporangium there is not much 

 evidence left. No trace of Microspores, or of paraffine, is now to be seen in it. The 

 scale is chiefly formed of cellular tissue, enclosing in its centre a bundle of vascular tissue, 

 which is shown in the specimen to proceed from the axis and to traverse the scale to its 

 apex. Tills latter is broad, dilated at right angles to the pedicel, and produced upwards 

 into a triangular acute point, and downwards into a blunt lobe, as described by Dr. 

 Hooker in his Lepidostrobus. 



Fig. 9 is the longitudinal section of the inner portion of the central axis of the Cone, 

 magnified twenty-eight diameters. 



In both specimens. No. 17 and No. 19, the chief value of the information they afford 

 is in the structure of the axes of the two Cones. In the specimens treated of by Dr. 

 Brown, Dr. Hooker, and MM. Brongniart and Schimper, the upper portions of the Cones 

 (so far as the scales or bracts and Sporangia are concerned) have been fully described by 

 the two former authors, and the whole of the Cone by the two latter ; but there is no 

 complete description of the structure of the central axis. My specimens appear to me 

 to supply to a great extent that deficiency. We have seen how the whole of the specimen 

 "No. 17" not only agrees with that of Dr. Brown, but that its axis is identical in 

 structure with that of Lepidodendron Ilarcourfii. M. Brongniart appears to think that 

 Dr. Brown's specimen was merely the upper part of a Cone similar to his, called by 

 Prof. Schimper Lepidostrobus Babadiatius. If this should be proved to be the case, both 

 my "No. 17 " and Dr. Brown's specimen may probably prove to be the upper portion of 

 a Cone Avith Sporangia containing Microspores, having its lower portion composed of 

 Sporangia containing Macrospores, and thus prove that all these three cones are the 

 fructification of Lepidodendron, and, not unlikely, that of L. Harcourtii. 



No. 19 bears considerable resemblance in structure, so far as its central axis is con- 

 cerned, to the stem of Lepidodendron vasculare (see below) ; and therefore it is here 

 referred to that plant, but not without doubt. One thing is certain that, although 

 ^externally it is like No. 17, it is quite a different Cone so far as its internal structure is 

 concerned. This specimen also, probably owing to its advanced stage of growth, had 

 shed its Spores before it was mineralized. 



Specimen No. 20 ; Lepidodendron vasculare. Plate VIII, fig. 6. 



Fig. 6 is a transverse section of the inner portion of a stem of Lepidodendron vasculare, 

 magnified twelve diameteis, showing the centre, composed of hexagonal tubes of barred 



