SPHENOPHYLLALES 



[CH. 



alternation of foliage leaves and sporophylls in Tmesipteris 

 and in Lycopodium Selago. 



Another form of cone, also from the Middle Coal Measures, 

 is referred by Kidston to Sphenophyllum trichomatosum Stur^ 

 (fig. 113, B): this is characterised by the more horizontal 

 position of the bracts, which " do not appear to be so much or 

 so suddenly bent upwards in their distal portion as in some 

 other species of Sphenophyllum" and by sessile sporangia 

 borne singly on the upper face of each bract. 



A more recent addition to our knowledge of the fertile 

 shoots of Sphenophyllum is due to Scott who has described a 

 new type of cone under the name Sphenophyllum fertile'^. The 



Fio. 114. Sphenophyllostachys fertilis (Soott). (After Scott.) Diagram of a 

 node in longitudinal section, showing one sporophyll and the base of the 

 opposite one. v.l. ventral lobe of sporophyll ; v.s. one of the segments into 

 which it divides ; v.s'. stump of another segment ; d.l. dorsal lobe ; 

 d.s., d.s'. segments of dorsal lobe. 



petrified specimen on which the species was founded was 

 discovered by Mr James Lomax in the Lower Coal Measures of 

 Lancashire ; it represents a portion of a cone 6 cm. long and 

 approximately 12 mm. broad. The axis contains a single 

 vascular cylinder agreeing in essentials with the type of stem 

 structure known as Sphenophyllum plurifoliatum. The nodal 

 regions, which exhibit the slight swelling characteristic of the 

 genus, bear several (probably twelve) appendages connate at 



1 Kidston (91) p. 59, PI. i. ; (01) p. 123, fig. 22. 



2 Scott (05). 



