Manchester Memoirs, Vol. Ivi. (19 12), No. VZ- 



XII. On the Interpretation of the Vascular Anatomy 

 of the Ophioglossaceae. 



By William H. Lang, M.B., D.Sc , F.R.S., 



Barker Professor of Cryptogantic Botany in the University of Manchester. 

 ( Received and Read, April 2nd, igi2.) 



The affinities of the OphioglossaceK have long been a 

 disputed question. At first classed with the Ferns, they 

 were later compared with the Lycopodiales and Spheno- 

 phyllales. The work of Bower in examining and stating 

 the latter view remains of importance, although, owing to 

 the further evidence which has come to light, this investi- 

 gator has recently changed his theoretical views. It now 

 appears to be highly probable that the Ophioglossacea; 

 are Ferns and show special relationship with the extinct 

 group of the Coenopteridese (Botryopteridea^ and Z} g- 

 opterideai). They also have features in common with the 

 existing groups of the Osmundacese and Hymenophyl- 

 laceai and these also exhibit affinities with the Coen- 

 opterideK. The view that the Ophioglossaceae are related 

 to the Coenopterideae was stated by Renault in 1875, and 

 has been more recently expressed by Scott,' Bower" and 

 other investigators. 



This return to the earlier views as to the affinities of 

 the Ophioglossaceae has been brought about largely by 

 the facts regarding the vascular relations of the sterile 

 and fertile regions of the leaf and the structure of the 

 sporangia. While weight has also been attached to the 

 evidence obtainable from the general anatomy of the stem 



1 Studies in Fossil Botany. Plate II., Chap. XIV., p. 640. 

 " Annals of Botany, XXV. (1911), p. 296. 



June 4th, jgi2. 



