M. Brongniart on a Fossil Lycopodiacean Fruit. 77 



the fraction ^7, an arrangement which approaches that ob- 

 served in the leaves of many living Lycopodiaceae*. 



The scales or bracts which form this spike spring perpen- 

 dicularly from the axis, and are even a little reflexed ; they 

 have exactly the organization so well described by R. Brown 

 in his Triplosporites, and to which it seems to me useless to 

 revert ; as in his specimen they are bent up towards the extre- 

 mity and terminated at the surface of the fossil by an hexa- 

 gonal disk, which would, as in Lepidostrobus^ be produced into 

 a foliaceous appendage, which has been destroyed. 



Upon the narrow pedicels of these scales are inserted oblong 

 sporangia, rounded at the extremity as in Triplosporites • those 

 which occupy the apex and middle part of the spike are filled 

 with an innumerable multitude of little spores, formed by three 

 or sometimes four united spherical cells, apparently separating 

 in some cases into simple globular spores. 



In the lower third of the same spike we observe sporangia 

 similar in form and mode of insertion to the preceding, but 

 distinguished at once by their large, simple, spherical spores, 

 the diameter of which is ten or twelve times that of the cells 

 of which the little spores are composed. They are very dis- 

 tinct to the naked eye, their diameter being 0*6 millim., and 

 enable the sporangia to be at once distinguished from those 

 containing the microspores. 



These large and perfectly spherical spores have a thick 

 smooth wall ; they most frequently contain scattered globular 

 granules, the nature of which is difficult to determine, but 

 which appear to be connected with a state of immaturity ; 

 some, filled with an opaque matter, seem to be more advanced 

 ifi their development. 



This spike, therefore, like those of the Lycopodiacea? of the 

 genera Isoetes and Selaginella, presents sporangia of two 

 kinds : — those near the summit of the spike containing micro- 

 spores, that is to say, antheridia ; the others, situated towards 

 the base of the spike, containing macrospores or germinative 

 spores. 



The form and mode of insertion of the sporangia, their great 

 size, the considerable number of macrospores which they con- 

 tain, and the absence of any trace of a regular line of dehis- 

 cence cause these organs especially to resemble those of Isoetes • 

 but in the latter these sporangia are inserted upon the very base 

 of the leaves, which spring from a very short and bulbiform 

 stem. In the fossil plant, on the contrary, these sporangia are 

 borne by a kind of bracts or squamiform leaves united into a 



* I have indicated this mode of arrangement of the leaves of Lycopo- 

 diace?e in the ' Histoire des Vegetaux fossiles,' tome ii. p. 11. 



