14 Weiss, Xenophyton radicidosmii (Hick). 



is often the case in the rootlets.* This feature has 

 assumed some importance on account of Renault'sf state- 

 ment that it is not rare to find this apex connected with 

 a single strand of tracheids which, surrounded by a 

 sheath, make their way through the cortex to the exterior 

 of the rootlet. Solms Laubach.t in his account of the 

 stigmarian rootlets, expresses some doubt as to the 

 existence of such branches from the root-bundle, and he 

 had a right to maintain this attitude of reservation, as 

 neither he nor anyone else had "been able to find any- 

 thing of the kind before or since in material from 

 England, which has been examined over and over again," 

 and as he was unable to recognise the tracheid as such 

 with any certainty " in Renault's specimen." The lack of 

 corroborative evidence, if such branches are of frequent 

 or normal appearance, may have been due to the defective 

 preservation of the tissue of the middle cortex in most 

 stigmarian rootlets. Even in Renault's specimen that 

 tissue is not entirely preserved. 



In our present specimen, where this tissue is so strongly 

 developed and so well preserved, one is able to see {Plate 

 yiAW.^Fig. 3) in the middle cortex, opposite the protoxylem 

 group, a horizontally running structure, which I take to 

 be identical with the vascular branch described by Renault. 



On a more enlarged scale {Plate XIII., Fig-. 2), it will 

 be seen to consist of a row of tracheids, clothed by a 

 fairly distinct sheath which, however, I have not been able 

 to trace into direct connection with the inner cortex of the 

 rootlet. 



* Williamson, W. C. ("81) Plate LIIL, Fig. 19. 



t Renault, M. B. " Cours de botanique fossile," premiere annee, 

 p. I to, deuxieme annee, p. 64, and Fig. 5, Plate II. 

 ,, ,, Annalcs des sciences geologiques, 1S82, Plate II., 



Fig. 8. 

 X Solms Laubach ('91) p. 279. 



