44 
M. G. Sykes. 
elongated longitudinally in the direction of the axis of the stalk; no 
connection can however be traced between these and the sporophyll 
bundle. 
The cortex of the stem in L. selago is composed of loose spongy 
tissue, reminding one of the cortex of some Lepidodendra, 1 
PI. Ill, Fig. 3.) 
(b). Subselago. In this group the upper leaves only are fertile; 
the sporophylls differ slightly from the vegetative leaves, forming 
an indistinct terminal spike. 
L. squarrosum and L. dalhousianum were examined. The 
sporangia of both are large, and axillary in position. In the former 
species (PI. II., Figs. 3a and b), the sporangium is borne on a very 
short stalk, and the sporophyll is not specially modified for protective 
purposes (Text-fig. 4, V.); in the latter species the sporangium has a 
Text-fig. 4. II., III., IV. are drawn from sections of typical sporophylls of 
Euselago. II.— (L. selago) shews part of an elongated sporophyll, with a 
mucilage cavity in its base, bearing a very shortly-stalked sporangium. III.— 
(L. fontinalis), shows a very thick short sporophyll, with no mucilage cavity, 
bearing a sporangium with a slightly longer stalk. IV.— (L. dichotomum), is 
drawn from a very long, thin sporophyll, whose subtending sporangium is 
furnished with a long stalk. V., VI., drawn from sporophylls of Subselago. 
V.—is from a section of the short sporophyll of L. squarrosum, which has a 
mucilage cavity and bears a sporangium on a very short stalk. VI.—(L. 
dalhousianum) , shews a longer-stalked sporangium. Diagonal shading=mucilage 
cavity. 
1 Bower, 1893, Figs. 8a, 11, etc. 
