192 STUDIES IN FOSSIL BOTANY 



bundles passed out more horizontally than in Lepido- 

 strobus, having a somewhat arched course in approaching 

 the pedicel. The inner cortex and, in some cases, the 

 phloem are preserved : the middle cortex has often 

 disappeared, but when present sometimes shows a re- 

 markable structure, consisting of interwoven trabecular 

 filaments, connected with the inner and outer tissues, 

 and with the sheaths of the outgoing vascular bundles. 

 The outer cortex consists of fibrous sclerenchyma, 

 either continuous or forming a network, with a more 

 delicate tissue occupying the meshes through which the 

 leaf-traces passed out to the sporophylls. 



The other species, J>. majusculus, which is larger, 

 has relatively still shorter sporophylls ; as regards the 

 form and insertion of the sporangia, the two species of 

 Spencerites agree, but the spores themselves are smaller 

 in 5. majusculus, and of different shape, having the 

 form of quadrants of a sphere, with narrow wings along 

 the angles. Vegetative stems are known, which in 

 structure much resemble the axis of the Spencerites 

 cones. They are of the Lepidodendroid type, and 

 have something in common with the stems of Bothro- 

 dendron (see p. 200). 



The insertion of the sporangium by its distal end 

 on a ventral lobe of the sporophyll suggests a com- 

 parison with Sphenophyllales, but the absence of any 

 vascular supply to this lobe in the case of Spencerites 

 is a serious point of difference. 



Lepidostrobus and Spencerites are typical Lycopodi- 

 aceous strobili, as to the affinities of which no doubt can 

 arise. The well-marked heterospory of some species 

 (possibly of all) shows that these fructifications had 



