STRUCTURE AND AFFINITIES OF LEPIDOSTROBI. 455 



niart inferred that Lepidodendron could not be a Dicotyledonous plant. 

 The arrangement of its tissues clearly forbade its belonging to Mono- 

 cotyledones. The cylindrical form of many of their (erroneously so 

 called) cones was conclusive against their belonging to any coniferous 

 plant, where these organs are always truly conical ; whilst the form of 

 these organs and the arrangement of their parts entirely tallied with 

 Lycopodiaceoe. 



In the details of M. Brongniart' s description of the genus Lepi- 

 dostrobus, there are some errors which, with the aid of more copious 

 and perfect specimens, may now be corrected. It is satisfactory to 

 know, that these rectifications throw light upon certain important 

 points, in which it was supposed that this genus differed from any 

 existing vegetable, presenting a most anomalous feature. 



The first error then relates to the arrangement of the sporangia 

 upon the supporting scales ; they were imagined to be borne on the 

 under-surface of the scales,* a misconception probably arising from 

 mistaking the base for the apex of the cone, as shown at Fig. 2 a of 

 Tab. 23. — ( Vegetaux Fossile, vol. ii.) 



M. Brongniart further supposed the horizontal portion or pedicel 

 of the scale, to be very broad, and to surround the base and two sides of 

 the sporangium, which was thus enclosed between its own scale and 

 axis, on all but the upper surface. In the specimens I have examined, 

 on the contrary, the pedicel of the scale is exceedingly slender in com- 

 parison to its dilated apex, and of far less breadth than the sporangium, 

 whose point of attachment to it is so small, that it can seldom be divided 

 during slicing by the lapidary. 



Lastly, M. Brongniart hesitates on pronouncing the L. ornatus of 

 Lindley and Hutton to be Lycopodiaceous. If, however, as I suppose, 

 the specimen, figured at Plate 7, is rightly referred to that plant, its 

 affinities are undoubtedly with the other Lepidostrobi. 



With regard to the number of species of Lepidostrobus, comprised in 

 the Plates 3, 4, 7, 8, 9, 10, I do not recognize more than two, with any 

 degree of certainty. One of them is that contained in the trunk of 

 Lepidodendron (figured at Plates 3 and 4), and which is probably iden- 

 tical with the fragments figured in Vegetaux Fossile, (vol. ii., t. 23, 

 fig. 5 a, b). The second is the very long cylindrical cone, included 

 within the trunk of Lepidodendron elegans (figured at Plate 8, fig. 1), 

 and to which, in all probability, should be referred the cones Plates 7, 

 8, figs. 3 and 8, and Plate 10. This is allowing for great variation 

 in the length of the cone, in one species, not more, however, than may 

 be seen in very many of their existing allies the Lycopodia as the 



* Vegetaux Fossile, v. ii., p. 52. 



