CORDAITEAE 547 



was seated on a long slender stalk or peduncle ; 1 this 

 may have been developed during the ripening of the 

 seed. Our knowledge of the comparative morphology 

 of the Cordaiteae has unfortunately made little progress 

 in recent years, owing to the want of adequate material. 



In certain cases, characteristic heart-shaped seeds 

 have been found in connection with the inflorescences 

 of Cordaites. This has rendered it possible to identify, 

 with great probability, a certain number of the isolated 

 seeds, as belonging to this family. Such direct 

 evidence is very necessary, for, as we have already seen 

 (Chaps. X. and XL), a large number of the Palaeozoic 

 seeds belonged to Pteridospermeae, and, where they 

 were of the platyspermic type, may be extremely 

 difficult to distinguish from those of Cordaiteae. It 

 is also probable that the seeds of primitive Coniferae 

 and Cycadophyta (both of which groups already 

 existed, at least in the later Palaeozoic times) may be 

 represented among the detached seeds. We will first 

 describe that type of seed which is known, from the 

 evidence of attached specimens, to have been produced 

 by the Cordaiteae, and was therefore named Cordai- 

 carpus by M. Renault. 2 



These seeds are heart-shaped at the base, and some- 

 what flattened, being of the platyspermic type. The 

 testa is double, the outer envelope, or sarcotesta, having 

 been soft and fleshy during life, while the inner layer, 



1 Carruthers, " Notes on some Fossil Plants," Geol. Mag. vol. ix. 

 1872. 



2 These seeds were originally named Cardiocarpus by Brongniart, a 

 name used by Carruthers and Williamson in the form Cardiocarpon. As 

 pointed out in Vol. I. Chapter VI. (p. 194), certain "seeds" referred by 

 Williamson to Cardiocarpon really belonged to Lycopods and are now 

 named Lepidocarpon. 



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