232 Lang.— Studies in the Morphology and 
derived mainly from the adaxial xylem of the subtending leaf-trace, has 
thus been throughout in connexion with the xylem of the stem stele. 
As the branch stele becomes quite independent a certain amount of the 
xylem between it and the stele of the axis dies out in the cortex. As in 
the case of the first branch described, the stele of the branch at its base 
has a greater diameter than the stele of the main axis at the same level ; 
the branch stele soon diminishes in diameter. A slight development of 
pericyclic xylem occurs in the subtending leaf- trace (Text-fig. 1 3,$), but 
takes no part in the supply to the branch. 
The fourth case of branching in B. Lunaria that I have studied is 
of great interest, but unfortunately only a number of hand sections were 
available. I owe the specimen to the kindness of my friend Professor 
Text-fig. 13. Series of transverse sections of the third branching specimen. Description in text. 
Gwynne-Vaughan, who noticed the branching in some sections cut by 
a student in his laboratory, and obtained and arranged all the sections 
that had been cut of the piece of rhizome in question. The stout rhizome 
with typical adult structure of the stele had evidently been injured at the 
upper end, and the buds in the axils of the two uppermost leaves of 
the remaining portion of the xylem had developed as branches. The leaf 
below showed the usual vestigial axillary bud. The steles of the branches 
in this specimen were relatively small compared with that of the stele of 
the axis. 
The main rhizome had a large stele with a well-marked external 
endodermis. The broad band of xylem around the large pith showed the 
distinction of primary and secondary wood described above in other large 
stems. The arrangement of the elements of the primary xylem was very 
suggestive of a distinction of centripetal and centrifugal xylem. Outside 
