6 Stopes, a Neiv Fern from the Coal Measures. 



undergone "carbonisation " prior to its fossilisation,a zone 

 of smallish thin walled cells is to be seen just outside the 

 xylem. Of these, one or two rows have much the form of 

 the rather large celled metaphloem, frequent in living 

 ferns {sqq Fig. 5), and it is likely that they are the phloem 

 in this case. Pericycle and endodermis are not preserved 

 in any determinable form, but the presumption is natural 

 that they surrounded the vascular elements as in the 

 normal fern type. 



The cortex is in general less well preserved than that 

 of the petioles ; there is a large space between the stele 

 and those layers of the cortex which are preserved, which 

 may represent a more delicate inner zone. The cortical 

 layers present are composed of closely -fitting rounded 

 cells with rather thickened walls and no air spaces. I 

 have not been able to observe the epidermis. 



There seems to be nothing peculiar or even character- 

 istic about the outer zone of the cortex which might lead 

 to the correlation of this plant with any other impressions 

 or fragments, as neither zones of thickening, hairs nor 

 emergencies of any sort are to be found on it. 



Towards the upper end of the specimen the tissues 

 become much less clearly differentiated, and finally, though 

 still at least an inch from the actual apex, no xylem is 

 recognisable. The other tissues are less thick-walled and 

 the cells contain more small fragments which may repre- 

 sent cell contents, while many of them contain blackened 

 contents and others numbers of small roundish bodies 

 which may be starch grains (see p. 10 and compare i^z^. 9). 

 These appearances, combined with the smaller size and 

 number of the petioles surrounding the main axis (these 

 also appearing undifferentiated), lead to the conclusion 

 that the apical growing point is approaching. The series 

 of sections stops here because the preservation of the cen- 



