182 



THE MARATTIALES 



The separated xylems become joined lower down into a single transverse plate, just 

 before the junction of the strand with the trace from the third leaf (fig. i66, H), 

 with which it joins in the same way and is continued downward to the junction with 

 the strand arising from the fusion of the second leaf trace with the cotyledon. Above 

 the junction of the first and second leaves, the stele of the second root, which grows 

 vertically downward, joins the stele formed by the junction of the three youngest 

 leaf traces. 



Above the junction the section of the bundle is nearly circular in outline, the 

 large tracheids forming a broken group in the center of the bundle, quite like a 



Fig. i66. 



A-C. Series of transverse sections from a sporophyte of Kaulfmsia, of about same age as that shown in fig. i6c. 



D. Stem apex. £> j 



H-J. Three sections lower down. 



K. Central vascular cylinder still lower down. 



corresponding stage in Danaa. Some of the cells adjacent to the bundle show the 

 typical thickenings on the radial walls, indicating that they belong to the endodermis, 

 but the hmits of the endodermis are extremely vague. In this plant two mucilage 

 ducts had developed in the fourth leaf, one on each side of the vascular bundle 

 (fig. 1 66, B, m). 



The second root is stouter than the primary one and its bundle is triarch. The 

 mycorrhiza present in the first root could not be detected in the second root, but 

 possibly may be developed at a later stage. All of the roots are provided with root 



