468 



COENOPTERIDEAE 



[CH. 



The sporangia^ o{ Stauropteris oldhamia are exannulate and 

 nearly spherical, with a wall of more than a single row of cells ; 

 they occur at the tips of slender and doubtless pendulous 

 branchlets. The discovery by Scott ^ of germinating spores 

 (fig. 323) in a sporangium of this type supplies an interesting 

 piece of evidence in favour of the fern nature of these repro- 

 ductive organs. Similar germinating spores have been described 

 by Boodle^ in sporangia of Todea. 



Fig. 322. Sporangia of Stauropteris oldhamia. St, stomium : p, palisade 

 tissue. (From Tansley, after D. H. Scott, from a drawing by 

 Mrs D. H. Scott.) 



Stauropteris burntislandica. 



This Lower Carboniferous plant identified by Williamson 

 with the Oldham plant from the Lower Coal-Measures is 

 referred by Bertrand to a distinct species. In the structure 

 of the rachis stele it agrees closely with Stauropteris oldhamia ; 

 the main vascular strand gives off four rows of branches, two 

 from each side, and aphlebiae were present at the common 

 1 Scott (04) ; (05'). 2 Scott (06^). 3 Boodle (08). 



