96 



ANCIENT PLANTS 



In a few words, these are the main characters of 

 the large group of Cordaites, which held the dominant 

 position among Gymnosperms in the Palaeozoic era. 

 They have relationships, or perhaps one should say 

 likenesses, to many groups. Their stem- and root- 

 anatomy is similar to the Coniferae of the present day, 

 the position of the ovules is like that in the Taxaceae, 



the male cones in some 

 measure recall those of 

 Ginkgo, the anatomy of their 

 leaves has points which are 

 comparable with those of the 

 Cycads, to which group also 

 the large pith in the stem 

 and the structure of some 

 details in the seeds unite 

 them. Their own specially 

 distinctive characters lie in 

 their crown of huge leaves, 

 and unbranched shaft of 

 stem, the similarity of their 

 male and female inflores- 

 cences, and some points in 

 their pollen grains which 

 A, Axis with s, scales; c, coat of the have not been mentioned. 



seed, from which the inner parts have The type is a Very COmplcX 

 shrunk away; n, nucellus; /.r, pollen nosqihlv rnmincr near 



chamber containing pollen grains which '^"^' POSSlDiy COming near 



enter through m. the stock which, having 



branched out in various 

 directions, gave rise to several of the living families. 



Plants which come very near to the Cordaiteae are 

 the PoROXYLE^. Of this group we have unfortunately 

 no remains of fructifications in organic connection, so 

 that its actual position must remain a little doubtful 

 till they are discovered. There seems no doubt that 

 they must have borne seeds. 



Still, it has been abundantly demonstrated in recent 

 years that the anatomy of the root, stem, and leaves 



Fig. 64. — Representation of Cordaites 

 Seed and its Axis with Scales, slightly 

 diagrammatic, modified from Renault. 



