LIXNEAX SOCIETY OF LONDON. 57 



On tht! Structure of the Stem aud Leaf of Nnytsia jloribunda, 



R. Br. By E. J. Schwartz, E.L.S. 



[Eeacl 5th April, 1906.] 



NvYTSiA FLOBwrxDA is a member of the Loranthacese aud a native 

 of West Australia : unUke other members of this order, it is non- 

 parasitic and a tree attaining a height of some 30 feet. The 

 leaves are linear-acute, of length about 1 inch, and the stomata, 

 which are in more or less regular rows, are transverse to the leaf- 

 axis. In section, the leaves show a meristele of three bundles 

 embedded in a water-storing tissue which is in turn surrounded 

 by the assimilatory tissue ; one or more resin-sacs are to be found 

 alDOve the bundles. The stem has many points of interest — a 

 heterogeneous strongly thickened and pitted pith containing a 

 central resin-canal proper to the stem itself, accompanied b}' three 

 or more perimeduUary canals ; islands of phloem and cambium 

 embedded in secondary xylem ; and a cork of epidermal origin, — all 

 points of difference from the other members of the Loranthaceue. 

 The assimilatory tissue throughout the plant is I'ich in tannin, 

 and no calcium-oxalate crystals are to be found in the stem. 



The paper was illustrated by slides from photographs of the 

 author's preparation. 



TI. 



The Affinities of Pteridosperms and Gymnosperms. 

 By Dr. D. H. Scott, F.E.S., Sec.L.S. 



[Eead 3rd May, 1906.] 



As an advocate, for the last ten years, of the Filicinean origin 

 of Cycads, and probably of Gymnosperms generally, I should like 

 to remove a misapprehension which appears to exist in some 

 quarters. It was suggested in 1895 that the Cycadotilices 

 Lyginodendron and Beterangmm were the " derivatives of an 

 ancient and geuerahzed (or rather non-specialized) Tern-stock," 

 and in lby9 the opinion was expressed that this " common stock 

 was to be sought among simple Ferns or Fern-like plants." At 

 no time has it been held that the Cycadofilices or Pteridosperms, 

 to use the current name, sprang from any family of Ferns already 

 known, still less from any family represented in the recent Flora. 

 So far as the morphological evidence is concerned, the position 

 is unaltered at the present time. The important discoveries of 

 the seeds of the Pteridosperms scarcely touch this question, for 



