2 SPHENOPHYLLALES [CH. 



be of sufficient importance to warrant specific separation, are 

 forms of one species or portions of specifically distinct cones. 

 It has been pointed out by Scott' that the strobilus known as 

 Sphenophyllostachys Dawsoni probably includes two distinct 

 species, one being the cone of SphenophyUuni cuneifolium 

 Sternb., and the other the cone of S. myriophyllum Cr^p^. 

 The stem of 8. myriophyllum agrees anatomically with the type 

 known as Sphenophyllum plurifoliatum Will, and Scott^. 



Fio. 112. Sketch of a radial longitudinal section of Sphenophyllostachys. 

 There are usually two concentric series of sporangia on the sporophylls, 

 not three as shown in the iigure. The upper figure (after Zeiller) shows 

 the linear bracts in surface-view. 



In addition to the two types of cone already mentioned, 

 Sphenophyllostachys Dawsoni and S. Romeri, others have 

 been described by Kidston from carbonised impressions. One 

 of these is the fertile branch of SphenophyUuni majus^. The 

 basal portions of the bracts of each whorl form a narrow collar 

 round the axis of the cone ; the free portion of each bract 

 consists of a lamina divided into two equal bifid lobes bearing 



1 Scott (05) p. 34. 



2 ZeiUer (88) A. PL lxii. figs. 2—4. 



3 Vol. I., p. 397. 



* Kidston (01) p. 128, fig. 25 ; (02) p. 361, fig. 13. 



