TRANSACTIONS OF SECTION K. 921 



ancestry and the descent of our existing flora. To begin with the angiospermous 

 aowering plants, it has been ascertained that they make their first appearance in 

 tlie bretaceous epoch, but we have no clue as to their origin. The relatively late 

 appearance of Angiosperms in geological time suggests that they must have spruno' 

 trom an older group, such as the Gymnosperms or the Pteridophyta ; but there il 

 no evidence to delinitely establish either of these possible origins. Then as to the 

 origin ot the Gymnosperms, whilst it cannoD be doubted that thev were derived 

 trom the Pteridophyta, the existing data are insufficient to enable us to trace 

 their pedigree. The most ancient family of Gymnosperm.s, the Cordaitacea, can 

 be traced as far back as any known Pteridophyta, and cannot, thereibre, have been 

 derived irom them • but the fact that the Cordaitace^ exhibit certain cycadean 

 attimties, and the discovery of the Cycadofilices, suggest that what may be termed 

 the cycadean phylum of Gymnosperms (including the Cordaitace£e, Bennettitaceje, 

 Gycadacese, and perhaps the Ginkgoacete) had its origin in a filicineous ancestry 

 ot which. It must be admitted, no forms have as yet been recognised 



lurning to the Pteridophyta, the origin of the Ferns is still quite unknown : 

 the one tact which seems to be clear is that the eusporangiate forms (Marattiacea;) 

 are more primitive than the leptosporangiate. With regard to the Equisetin^ 

 the Galamariacese were no doubt the ancestors of the existing and of the fossil 

 iiquisetums. Similarly, in the Lycopodinte, the palfcozoic Lepidodendracefe were 

 the lorerunners of the existing Lycopodiums and Selaginellas. The discovery of 

 t^e bphenophyllaceas seems to throw some further light upon the phylogeny of 

 these two groups, inasmuch as these plants possess characters which indicate affinity 

 with both the Equisetinje and the Lycopodinse, thus suggesting the possibility that 

 they may have sprung from the same ancestral stock. ° *= ^ ^ 



11 1 .'^'^.^P^?^'' ^^^ geological survey of the vegetable kingdom I will briefly 

 allude to the Bryophyta and the Thallophyta. Owing no doubt to their delicate 

 texture, the records of these plants have been found to be very incomplete. So 

 much IS this the case with the Bryophyta that I forbear to make any statement 

 concerning them The chief point of interest with regard to the Fungi is that 

 most ot those which have been discovered in the fossil state were found in the 

 tissues of woody plants on which they were parasitic. In this way it has been 

 possible to ascertain, with some probability, the existence of Bacteria and of 

 mycelial Fungi m the Paleozoic period. The records of the Algaj are more satis- 

 lactory : they have been traced far back into the Paleozoic age, where thev are 

 lepresented by siphonaceous forms and by the somewhat obscure plants known as 

 iSematophycus and Pachytheca. 



In a general way the study of Palteobotany has prwed the development of 

 higher trom lower forms in the successive geological periods. Thus the Tertiary 

 and Quaternary periods are characterised by the predominance of Angiosperms, 

 lust as the Mesozoic period is characterised by the predominance of Gymnosperm.s, 

 and the Paleozoic by the predominance of Pteridophyta. And yet, as I have been 

 pointing out we are not able to trace the ancestry of any one of the larger groups 

 ot pjants. Ihe chief reason for this is that the geological record, so far as it is 

 Known, has been found to break off' with such surprising abruptness that the ear- 

 Jiest, and therefore the most interesting, chapters in the evolution of plants are 

 Closed to us. Alter the wealth of plant-forms in the Carboniferous epoch there is 

 a striking talling-ofl- m the Devonian, in which, however, plants of high organisa- 

 tion, such as the Cordaitacefe, the CalamariaceiB, and the Lepidodendraces, 

 SHU occur, in the Silurian epoch vascular plants are but sparingly present 

 —but It 13 remarkable that any such highly organised plants should be found 

 Tiiere— together with probable Algaj, such as Nematophycus and Pachytheca. The 

 oambnan rocks present nothing but so-called ' Fucoids,' such as Eophyton, &c., 

 some of which may be Algse. The only known fossil in the oldest strata of all 

 tne Archaean, is the much-discussed Eozoon canadense, probably of animal orio-in • 

 but the occurrence here of large deposits of graphite seems to indicate the existence 

 ot a coiisiderable flora which has, unfortunately, become quite undeterminable, 

 -inus, whilst there is some evidence that the primitive plants were Algre, there ia 

 at present no available record of the various stages through which the Silurian and 

 Devonian vascular plants were evolved from them. 



