POROXYLEAE 513 



displaying the characters of the platyspermic type. 

 The discovery, if confirmed, will considerably strengthen 

 the affinity otherwise indicated between the Poroxyleae 

 and Cordaiteae. 



MM. Bertrand and Renault regarded the genus as 

 related, on the one hand, to Sigillaria, and, on the 

 other, to Cordaiteae. The affinity with the Cordaiteae 

 seems indisputable, as will appear when we come to 

 describe that family ; the relation to Sigillaria, however, 



V 



d. 



Fig. 185. — Rhalulocarfms sul'tunicatits Grand'Eury. Transverse section of seed, to 

 show the platyspermic type of structure, a, sclerotesta ; opposite the ridge (v) at 

 each side is a vascular bundle; c, sarcotesta, with numerous fibrous strands; d, 

 contracted nucellus, within which is the embryo-sac. x about 3. After Krongniart. 



though it appeared tenable at the time it was suggested, 

 and was supported by the case of Sigillai-iopsis, with 

 its double foliar bundle and occasionally pitted 

 tracheides (see Vol. I. p. 230), now seems to be excluded 

 by the manifest affinity between Poroxylon and the 

 Pteridosperms of the Lyginodendron group. As has 

 already been pointed out, and as the French observers 

 recognised, the agreement in structure between Poroxylon 

 and Lyginodendron is in many respects a close one, so 

 much so that there can scarcely be a doubt that the 

 two genera are allied. The same remark applies, to 



