A Contribution to our Knowledge of 
Lyginodendron. 
BY 
A. C. SEWARD, M.A., F.G.S. 
With Plates V and VI. 
MONG a number of specimens in the Botanical Depart- 
JL~\ ment of the British Museum referred to the genus 
Dadoxylon , I found one transverse section which had been 
cut from a thick stem possessing a large pith and a con- 
siderable development of secondary wood. An examination 
of the specimen revealed certain striking anatomical characters 
entirely at variance with those of Dadoxylon or Cordaites , but 
on the other hand indicative of a close affinity with the genus 
Lyginodendron . The section had been taken from an un- 
usually fine piece of fossil wood partially enclosed in argil- 
laceous limestone, having a length of 14 cm. and a breadth of 
14 cm. A portion of the exposed surface of the specimen 
consists of smooth and waterworn wood ; and where the 
fossil is enclosed by the surrounding matrix no trace of tissues 
external to the wood can be detected. 
The wood measures 5*8 cm. in the thickest part, and very 
probably when the stem was living it attained a still greater 
breadth, as there is no proof that the outermost portion as 
shown in the fossil represents the extent of the original woody 
tissue. The large pith lying towards one side of the block 
[Annals of Botany, Vol. XI. No. XLI. March, 1897.] 
