MaticJiester Memoirs, Vol. xlvi. (1902), No. 9. 15 



The first portion of the course of this lateral branch 

 is at right angles to the long axis of the root, but it 

 seems afterwards to become parallel, or nearly so, to the 

 axis of the root, if the little star-shaped group of cells 

 with the darker centre represents, as I take it to do, the 

 transverse section of this peculiar strand of tracheids with 

 its parenchymatous sheath. 



I have been unable to find an\- similar organs running 

 longitudinally in any other portion of the middle cortex, 

 and if they are given off from other portions of the xylem 

 strand, they would of course be at a different level, and 

 might not be visible in this transverse section. Indeed, 

 except where they run longitudinally, such delicate 

 vascular branches, consisting of a single row of tracheids, 

 would be excedingly difficult to recognise. It would be 

 easier to find such tracheids in the outer cortex or on the 

 surface of the root, if they run as far as that. But in the 

 present specimen no further trace of them can be seen 

 except that mentioned above and figured in Figs. 2 and 3 

 oi Plate XIII., and it is consequently uncertain what were 

 their course and their function in this rootlet, which differs 

 in many particulars from that figured by Renault. From 

 its appearance and mode of origin, I conclude that it was 

 an organ of some importance to the rootlet, and an 

 examination of stigmarian rootlets of the type figured 

 by Renault confirms his statement that its occurrence is 

 by no means rare. I hope to be able soon to complete 

 a detailed examination of this point, but may take 

 this opportunity of stating that the evidence I have at 

 present does not confirm Renault's view that these 

 vascular branches pass into secondary rootlets (radicelles), 

 but that in some instances, at any rate, they supplied a 

 plexus of tracheids running on the inside of the outer 

 cortex. 



