CHEIROSTROBEAE 115 



fructifications of which the structure is known. It 

 occurs side by side with the stems of Sphenophyllum 

 insigne, from which, however, it differs so much in 

 structure as to preclude all idea of any connection 

 between them. 



The structure is admirably preserved, so that the 

 whole organisation of the strobilus could be worked 

 out, though unfortunately nothing is known for certain 

 as to the vegetative organs on which it was borne. 

 The cone was a large one — from 3.5 cm. to 4 cm. in 

 diameter, and certainly exceeding 10 cm. in length. 

 Its whole organisation is exhibited in the diagrammatic 

 sections in Fig. 49. The axis, about 7 mm. thick, bore 

 numerous, crowded verticils of modified leaves or 

 sporophylls, of which there were about twelve in each 

 whorl, the number diminishing towards the apex ; the 

 members of successive whorls were accurately super- 

 posed in vertical series, as in Sphenophyllum. The 

 sporophylls were compound, and indeed remarkably 

 elaborate in form and structure, so much so as to differ 

 widely from any other organs to which the name is 

 applied. The important point is, that in Cheirostrobus, 

 each sporophyll was subdivided in two planes ; immedi- 

 ately above its base it branched into an inferior and a 

 superior lobe, while at the same time both lobes sub- 

 divided, in a palmate manner, into segments. The 

 total number of segments was usually six, of which 

 three belonged to the lower lobe, and three to the 

 upper, the latter lying directly above the former (see 

 diagram, Fig. 49). The sporophyll attained a length 

 of 1.4 cm. or more, almost the whole of which was 

 occupied by the free segments, for the common basal 



