588 ON TRIPLOSPORITE, 



I cannot at present enter fully into the question of the 

 affinities of Tripolosporite . I may remark, however, that 

 in its scalariform vessels it agrees with all the fossil genera 

 supposed to be Acotyledonous. In the structure of its 

 sporangia and sporules it approaches most nearly, among 

 recent tribes, to LycopodiacecE, and Ophioglosseae ; and 

 among fossils, no doubt, to Lepidostrobus, and conse- 

 quently to Lepidodendron. 



The stem structure of Lepidodendron, known to me only 

 in one species, Lepidodendron Harcourtii, offers no objec- 

 tion to this view, the vascular arrangement of the axis of 

 its stem bearing a considerable resemblance to that of 

 Triplosporite. To the argument derived from an agree- 

 ment in structure between axis of stem and of strobilus I 

 attach considerable importance, an equal agreement existing 

 both in recent and fossil Conifers. 



■173] In conclusion I have to state, that very recently (since 

 the drawings were completed, and as well as the specimens 

 seen by such of my friends as were interested in fossil 

 botany) Dr. Joseph Hooker has detected in the sporangia 

 of a species referred to Lepidosirohus sporules, and those 

 also united in threes. There are still, however, charac- 

 ters which appear to me sufficient to distinguish that genus 

 from the fossil here described. 



To the brief account here given of Triplospiorite it is 

 necessary to add a few remarks on some nearly-related 

 fossils, chiefly Lepidostrohi, whose structure is now more 

 completely known than it was when that account was sub- 

 mitted to the Society. 



On the affinities of Lepidostrobus to existing structures, 

 respecting which various opinions have been held, it is 

 imnecessary here to advert to any other than that of M. 

 Brongniart, which is now very generally adopted, namely, 

 that Lepidostrobus is the fructification of Lepidodendron, and 

 that the existing family most nearly related to Lepidodendron 



