CORDAITALES i8i 



ophytes have branched leaves and unbranched stems. In external 

 appearance this contrast is very prevalent. 



In the Cycadophytes, the large pith, scanty wood, and large 

 cortex are characteristic from the first appearance of the phylum to 



Fig. 194. — Cordaianthus williamsonii: 

 longitudinal section of female strobilus, 

 showing sterile bracts and two ovules; X 10. 

 — After Renault.''''^ 



Fig. 195. — Cordaianthus 

 williamsonii: longitudinal 

 section of ovule, showing the 

 nucellus free from the integ- 

 ument. The lower part of 

 the nucellus was much de- 

 cayed before silicification 

 occurred, but it still shows 

 that there was an elongated 

 female gametophyte; X35. 

 — After RENAULT.'t^s 



its living members. In the Coniferophytes, the earlier members also 

 have a large pith, scanty zone of wood, and a large cortex; but there 

 is a tendency, even in the Cordaitales, to reduce the pith and cortex 



