MEDULLOSEAE 



451 



discovered by Mr. Kidston, in nodules from the Middle 

 Coal-measures of Dudley, attached to a rachis bearing 

 the characteristic pinnules of Neuropteris heterophylla l 

 (Fig. 169). The specimens are casts, not petrifactions, 

 so no detailed study 

 of structure has been 

 possible, but the ex- 

 ternal characters leave 

 no doubt that the 

 organs in question are 

 seeds. They are of the 

 radially symmetrical 

 type, and the testa 

 has a fibrous structure. 

 Chiefly on account of 

 the latter character 

 Mr. Kidston refers the 

 seeds to the genus 

 Rhab do carpus of 

 Goppert and Berger." 

 The seeds appear to 

 be borne terminally 

 on the fertile branches 

 of the rachis ; it is a 

 striking fact that the 

 seed-bearing frond or 

 pinna should be so 

 little modified as to show the same form of pinnule 

 as the vegetative foliage ; the differentiation of the 



1 R. Kidston, ''The Fructification of Neuropteris heterophylla" Phil. 

 Trans. Royal Soc, B, vol. cxcvii. 1904. 



2 Brongniart, however, limited the genus Rhabdocarpns to seeds with 

 bilateral symmetry (Platyspermeae of Oliver), see Fig. 185, p. 513. 



30 



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Fig. 169. — Neuropteris heterophylla. Seed, at- 

 tached to a branch of the rachis bearing two 

 characteristic pinnules. X 2. After Kidston. 



