76 M. Brongniart on a Fossil Lycopodiacean Fruit. 



only very limited portions of these spikes ; some, however, 

 appear to have been preserved throughout their whole 

 extent, and there is nothing to indicate any difference of 

 structure between the base and the apex. Throughout, the 

 scales bear sporangia of the same form, and apparently en- 

 closing bodies of the same nature 5 this at least is indicated 

 by the figures and descriptions published by the learned 

 English botanist. 



These characters, therefore, seem to approximate the Lepi- 

 dostrobi to the true Lycopodia, of which all the sporangia are 

 similar and contain identical spores. 



The family Lycopodiacege includes two other genera, which 

 are very different in this respect, Selaginella and Isoetes, 

 which, on the same stalk or in the same spike, in one word, 

 on the same axis, present sporangia of two kinds, some con- 

 taining very small spores destined to produce antheridia and 

 to perform the function of fecundating organs, and the others 

 larger spores, which will germinate after being fecundated. 

 These two kinds of organs, which cooperate in reproduction, 

 have been designated by the names of microspores and macro- 

 spores. 



Nothing in the specimens described either by B. Brown or 

 by Dr. J. Hooker would indicate this double nature of the 

 sporangia or of the spores ; but a very complete and generally 

 well-preserved specimen of a spike identical in its upper part 

 with the Triplosporites of R. Brown has just thrown a new 

 light upon this subject, and shown in these fossils modifica- 

 tions analogous to those which we observe in the living Lyco- 

 podiaceae. 



This remarkable specimen was found in a drift deposit 

 at the entrance of the valley of Volpe, in the Haute-Garonne, 

 by M. Dabadie ; it was communicated to me by M. Lartet, to 

 whom it had been confided by M. Dabadie ; and the author of 

 this interesting discovery has been kind enough to allow me to 

 have it sawn through its long diameter, and to retain one-half 

 for the museum. This specimen, which was carefully modelled 

 before being cut through, is entirely silicified : the organiza- 

 tion of the various parts is well preserved in many points ; 

 nevertheless its anfractuosities and crystallized portions do not 

 allow it to be examined equally well in all parts. 



It presents the form of a cylindrical cone or strobile, 0*12 

 metre in length and 0*055 metre in breadth, showing on 

 the outside the apices of the scales of which it is composed ; 

 these form twenty-seven perfectly regular longitudinal rows, 

 and are arranged in accordance with a very much flattened 

 helix, the generative spiral of which would be expressed by 



