TJic Fossil Plants of the Coal Measures. 1 1 7 



each sporangium are most characteristic and unique. In 

 its young state it appears to me that each sporangium has 

 developed in its interior a number of cells which, collectively, 

 seem to have been the representatives of an Archesporium. 

 Each of these archesporial cells seems to have developed a 

 cluster of apparently four daughter cells, which were spor- 

 angiferous. But only one of each of these clusters has 

 come to maturity ; the result being that in every instance 

 we find a single spore surrounded by three, possibly more, 

 sterile sister cells (see Memoir I., Fig. 57, C.N. 631, and 

 Memoir B.B., Figs. 43-44, C.N. 6246). Each spore has a 

 diameter of about 1*4 mm. 



As already remarked, no traces of leaves or of branch- 

 ing specimens have yet been discovered. That leaves of some 

 kind have existed is clear from the presence of numerous 

 leaves-traces. Hence a suggestion made in my Memoir 

 Q. — p. 199, apparently continues to be true. 



Vegetative Organs. 

 Primary Tracheal Cylinder. 

 Transverse Sections. 



Medulla. 



BB. — Fig. 41, C.N. 6246. Medulla absent from some sections, e.g.y 

 C.N. 419b. 



Primary Tracheal Cylinder. 



Q. — p. 199, Fig. 19a, C.N. 419b. Medulla absent from this twig. 



Sporangiophores. 



I. — p. 340, Fig. 53c,c',c",c"', C.N. 626. 

 I.— p. 340, Fig. 54c', c", C.N. 629. 

 I.— p. 340, Fig. 55c',c", C.N. 631. 

 I.— p. 340, Fig. 56c',c". See C.N. 624b. 

 K. — p. 501, Fig. lie, C.N. 624. 

 BB.— p. 25, Fig. 5oe,e', C.N. 624b. 



Sporangia. 



I.— p. 341, Fig. 53d, C.N. 626. 

 I.— p. 341, Figs., 55d and 57d, C.N. 636. 

 I.— p. 341, Fig. 38. 

 K.— Fig. lie, C.N. 624. 

 BB.— p. 25, Fig. 5of,f',f", C.N. 624b. 



