XXVIl] 



GLOSSOPTERIS 



501 



sporangia, whether they contained microspores or whether they 

 are the spore-capsules of a homosporous plant. 



The rhizome of Glossopteris Browniana has been described 

 in detail by Zeiller, who first demonstrated that the fossils 

 originally assigned by Royle^ to the genus Vertebraria represent 

 the stem of this and, as we now know, of some other species of 

 Glossopteris. Vertebraria occurs in abundance in Permo-Car- 

 boniferous strata in association with Glossopteris; the differences 

 between Australian, Indian, and South forms, though expressed 



Pig. 336. Glossopteris Browniana, Brongn. Sporangia. ( x 30). After Arber. 



by specific names, are insignificant. The stems are usually pre- 

 served in the form of flattened, single or branched, axes sometimes 

 bearing slender branched roots and characterised by one or two, 

 or less frequently three, longitudinal grooves or ridges (fig. 337) 

 from which lateral grooves or ridges are given off at right angles, 

 dividing the surface into more or less rectangular areas 1 cm. or 

 more in length. The surface of these areas is often slightly 

 convex and in some specimens the outlines of cells may be 

 detected. Mr Oldham has described some interesting examples 



' Royle (33). 



