. SPORE-PRODUCING MEMBERS 323 
shows a structure similar to that of Lepidodendron Harcourtii,’ and though 
there is no direct indication of the source of the cone, comparison of the 
structure with that of Lepidodendron stems, and with other Lepidodendroid 
cones, leaves no doubt of its being the strobilus of a Lepidodendron.. The 
axis bears numerous sporophylls, of which thirteen are usually represented 
in each transverse section: the basal region of each extends horizontally 
from the axis, and supports the sporangium, which may extend for fully 
half an inch along its surface (Fig. 168). The distal end of the sporo- 
phyll turns upwards, without any peltate expansion. 
Fic. 169. 
Lepidostrobus Browni?. A=wall of sporangium, showing outer sclerotic cells (sc), 
with several thin-walled layers within. 100. A=three sporangia in transverse section 
of the cone ; x=median ridge. 3. C=cone in tangential section. D=sporangium in 
tangential section of cone, slightly diagrammatic ; s4=sporophyll; ~=sub-archesporial 
ridge; v, 8=vascular bundle ; 4=processes rising from the ridge. 6. A=small part of 
the base of a sporangium in radial section, showing the processes 4, A, which rise from it. 
X 20. 
Comparison of transverse and tangential sections of the cone (Fig. 
169 B,C) gives a clear idea of the form of the very large sporangium, 
which is a radially extended body, broader and deeper at the distal end 
than at the proximal; it is attached throughout its length by a relatively 
narrow median, flange-like insertion to the upper surface of the sporophyll, 
and immediately above the course of its vascular bundle. Comparison of 
its outline with that of the sporangium of Jsoefes shows a very striking 
similarity ; but this is not limited to the form only: in LZ. Brown? above 
1Or to that of Z. Williamson?, according to Solms Laubach, foss7/ Botany, Engl. 
ed., p. 226. 
