Notes . 
259 
podium described by Harvey Gibson in Selaginella \ These cells are 
well differentiated from the other cells of the ligule by their relatively 
large size and absence of contents, and between these clear cells and 
the ordinary tissue of the sporophyll are some large dense-looking 
cells, showing what appear to be conspicuous nuclei, which may be 
compared with the similarly situated dense cells shown by Harvey 
Gibson in Selaginella spinosa 1 2 . 
The base of the ligule is at a considerable distance from the leaf-trace 
bundle, and I can see no trace of tracheides or barred cells either in 
the ligule itself or in the tissue intervening between it and the leaf-trace 
bundle. There is no evidence of any special arrangement of the 
vascular tissues in relation to the ligule such as is described by Harvey 
Gibson in Selaginella helvetica and other forms, but there is seen 
a distinct convergence of the cell-rows towards the point of insertion 
as shown in the drawing. 
To sum up then, the position of the ligule in Lepidostrobus , with the 
sporangium between it and the axis, is identical with that in Sela- 
ginella ; but, whereas in the latter genus it is quite close to the axis of 
the cone, in the former the great elongation of the sporangium which 
had taken place in the radial direction had of course carried the ligule 
with it, and so the latter comes to be situated near the periphery of the 
cone and at a considerable distance (1.5 centim.) from the axis. The 
whole of the horizontal (sporangium-bearing) portion of the sporophyll 
thus appears to be homologous with the short leaf-base or cushion on 
the vegetative stem. The ligule differs markedly from those exhibited 
on the vegetative leaves of L. selaginoides , &c., in the complete absence 
of a ligular chamber ; although, as can be seen in the drawing, it is 
overarched by the protuberant distal end of the sporangium. 
In conclusion, I have to express my indebtedness to Dr. Scott, F.R.S., 
for kind help. 
ARTHUR J. MASLEN. 
Royal College of Science, S.W. 
1 Contributions towards a Knowledge of the Anatomy of the Genus Selaginella , 
Spr. ; Part II, The Ligule : Annals of Botany, Vol. x. 
2 Loc. cit., Figs. 3 and 6. 
