349 ) 



XL— The Pinna-Trace in the Ferns. By R. C. Davie, M.A., B.Sc, late Robert 

 Donaldson Research Scholar in the University of Glasgow, Lecturer in Botany 

 in the University of Edinburgh. Communicated by Professor I. Bayley 

 Balfour, F.R.S. 



(MS. received May 4, 1914. Head June 1, 1914. Issued separately August 18, 1914.) 



(Plates XXXIII.-XXXV.) 



The relation of the leaf-trace to the vascular system of the stem in the Ferns has 

 been exhaustively investigated during the past fifteen years by various workers, 

 especially by Gwynne-Vaughan and Boodle in this country and by Jeffrey and his 

 pupils in America. The interpretations of the numerous types of Fern stele and 

 leaf-trace have caused much discussion. And the discovery of a wonderful series of 

 fossil Ferns has not settled the discussion of the evolution of the Filicinean vascular 

 system, but has carried the battle on to another field. 



The fossils have recently yielded up the structure of their pinna-traces (Kidston, 

 '08 ; Bertrand, '09 ; Gordon, '11). Simultaneously an attack has been made on the 

 pinna-traces of living Ferns. Various pinna-traces were described in curious mathe- 

 matical formulae, but no comparisons were made of the different types, by Bertrand 

 and Cornaille ('02) in their Etude sur quelques caracteristiques de la structure 

 des Filicinees actuelles. Tansley in 1908 drew attention to the Fern leaf as the 

 stronghold of many anatomical problems, and reproduced in detail almost the only 

 account of the departure of the pinna-trace, that of Matonia pectinata, R. Br., by 

 Seward ('99). Compton in 1909 described the branching of the leaf of Matonia 

 sarmentosa, Baker, and figured the departure of the pinna-traces. Chrysler in 

 1910, in making comparisons among the Ophioglossacese, referred to pinna-traces in 

 the Osmundacese and Polypodiacese, while Sinnott in the same year described the 

 pinna-traces of some of the Osmundacese. In 1911 Sinnott made a rapid survey of 

 the Filicinean leaf-traces, briefly referring to the relation between them and the 

 pinna-traces. Gwynne-Vaughan ('11) amplified some of the American work on the 

 Osmundacese and made the first contribution to the knowledge of the pinna-trace in 

 ontogeny. In 1912 Bower described in detail the pinna-traces of Lophosoria pruinata, 

 Pr., and Gleichenia linearis (Burm.) Clarke, and placed some weight upon the 

 structure of the pinna-trace as a phyletic criterion. In working through the vascular 

 anatomy of Peranema cyatheoides, D. Don, I found a difference in the type of 

 pinna-trace departure in the basal and terminal pinnae, and, following the lead of 

 Chrysler ('10, p. 5), named the one " extramarginal " and the other "marginal" 

 (Davie, '12). 



In the marginal type the first indication of the preparation for the departure of 

 TRANS. ROY. SOC. ED1N.. VOL. L. PART 11. (NO. 11). 48 



