298 



TllK JOTJBNAI OF BOTANY 



As a palaeontologist, Dr. Scott dec-lines to follow Bateson and 

 Lotsy in the abandonment of all attempts al phvlogenetic reconstruc- 

 tion. He has obviously been much impressed by Dr. Church's essay 

 on " Thalassiophyta and the Sub-aerial Transmigration," and accent's 



the suggestion that the transmigrant races, the ancestry of the land- 

 flora, may have been Green Algae of a grade of organisation as high as 

 that now exhibited by the highest of the Brown. The most" 1 im- 

 portant part of the address was, perhaps, the sketch of the remarkable 

 results, not yet all published, obtained by Messrs. Kidston and Lang 

 from beautifully-preserved fossil plants in the Lower Old Red Sand- 

 stone chert of Rhynie, and the discussion of their phvlogenetic 

 implications. These plants were only partly known to* the late 

 Prof. Arber when preparing his posthumously published Devonian 

 floras m which he styled them " Procormophyta ' ; and the some- 

 what wKlely-varying structure of the genera now known has very 

 broad bearings on morphology as well as on phylogeny. They 

 possess distinctly vascular stems with stomata, though* rootless and 

 in most cases leafless. As, however, they were peat plants, some of 

 their characters may be due to reduction ; and, even without carrvim-- 

 back the original transmigration from sea to land, as Dr. Church 

 does, to pre-Cambrian times, we must admit that the Old Red Sand- 

 stone is far too late for the survival (which Messrs. Kidston and 

 Lang appear to maintain) of original transmigrants. The terminal 

 sporangia in Rornea and Rhynia are clearly only altered ends of 

 branches comparable to the stichidium of' the " Florideaj, which 

 renders Goebel's view of the sporangium as an organ mi generis no 

 longer tenable; and we seem to see branches of a thallus developing 

 into fertile fronds, and flattened barren pinnules with lamina- as 

 a later development. Dr. Scott frankly admits that his former view 

 that the Gymnosperms were derived, through the Pteridosperms 

 from the Ferns, must be given up. and that i! is safer to regard Seed 

 Plants as a stock probably as ancient as any phylum of Pterido- 

 phyta. 



Our knowledge of Pteridosperms has so far advanced since 1903-G 

 that eight families are now known, live of them from the Lower 

 Carboniferous. While maintaining the combination of these in one 

 phylum, Dr. Scott concluded his most suggestive address by con- 

 trasting the polyphyletic views of Arber (who traced back four lines 

 of descent to Thallophytic Algae, viz. Sphenopsida, Pteropsida 

 Lycopsida, and Psilotales), and still more of Dr. Church, who says 

 that "all the main lines of what is now Land Flora must haw been 

 differentiated in the Benthic epoch of the sea (». e. as algal lines) " 

 with the monophyletic views of Messrs. Kidston and Lang, who see 

 mAsteroxylon a generalised type linking Psilotales, Lycopodiales, and 

 Filicales, and in Rhynia and Rornia a much simpler type suggesting 

 " the convergence of Pteridophyta and Bryophyta backwards to an 

 Algal stock." 



The whole address demands a careful perusal by all students of 

 genetics, morphology, or taxonomy. 



Cr. S. B. 



