LIN?fEATf SOCIETY OF LOXDOX. 53 



Shoetia, Terr, ifc Gray, in Am. Journ. Sc. ser. I. xlii. (1S42) 48 ; 



et ser. II. xlv. (1868) 402. 

 Davidi, Franch. in Nouv. Avch. Mus. Par, ser, 11. x. (1887) 



t. 13 B = Berneuxia thibetica, Decne. 

 galacifolia, Torr. S,- Graif, I. c. — Am. bor. 

 rotundifoUa, Makino, in Tokyo, Bot. Mag. ix. (1895) 327 ; 



et X. (1896) 22l=Scliizocodou rotundifolius, Maxim. 

 sinensis, Hemsl. in Hook. Ic. PI. t. 2624. — Yunnan. 

 thihetica, Franch. in Nouv. Arch. Mus. Par. ser. II. x. (1887) 



54, t. 13 B (Z)rtyK7i)=Berueuxia thibetica, Decnc. 

 uniflora, Maxim, in Bull. Acad. Petersh. xvi. (1871) 225. 



— Japon. 



II. 



The Origin of Gymnosperms. 

 By Prof. F. W. Oliver, F.E.S., F.L.S. 



[Eead lotli March, 1906.] 



The inA'-estigations of Hofmeister have been regarded as settling 

 once for all the general relation of affinity between the Gymno- 

 sperms and Vascular Cryptogams. Critical analysis of this work 

 and later contributions in the same field have led to the recognition 

 of several distinct lines of descent Mithin the latter class, and at 

 one time and another each of these lines has been favoured as 

 that from which the Gymnosperms arose. In recent times, the 

 balance of opinion has set in the direction of the Ferns, the point 

 of closest contact being found in the Cycads. The view has 

 gained material support through the discovery of multiciliate 

 spermatozoids in the last-named group and in Ginlr/o, as well as 

 from the recognition of the existence in Palaeozoic times of an 

 extensive plexus of forms (the Cycadofilices) which, whilst 

 retaining tlae habit and many of the structural peculiarities of 

 Ferns, show a distinct advance in the direction of the Cycads. 

 Now that evidence has come to light proving that many of the 

 forms there included were seed-beai'ing plants, the foundation of 

 a new Class, the Pteridospermeae, has been judged expedient for 

 these Spermopbytes which have so much in common with the 

 Ferns. 



As matters are shaping at the present time, it would appear 

 that certainly a preponderating number of so-called Palteozoic 

 " Ferns " are in reality Pteridosperms which have been hitherto 

 confounded with true Ferns in view of their frond-like habit and 

 lack of distinguishing organs of reproduction. The existence of 

 a great reserve of supposed Ferns in the older rocks has served as 

 a material bulwark to the ilofmeisterian doctrine of the passage 

 of Pteridophytes into Sperm.ophytes. But if the Palteozoic is in 

 reality the "age of Pteridosperms'" rather than the "age of 



