ADULT ANATOMY OF WELWITSCHIA MIRABILIS, 339 
and pass down into the hypocotyl. Others pass out between the leaf-bundles under the 
base of the groove and supply the inner ridge and its inflorescences. On their way some 
of these bundles form connections by means of secondarily developed vascular elements 
with the secondary tracheids &c. of the leaf-bundles. 
In these later stages it is not possible to follow accurately the course of the common 
bundle-supply of the two ridges in a downward direction. Free endings are rarely met 
with, but some of the bundles can be traced down below the level of the feeder before 
they fuse with the bundles of the hypocotyl. 
Vascular Supply of the Young Inflorescence.—I was able to investigate the vascular 
supply of the young inflorescence * seen in Pl. 34. fig. 9. Its axis received a number of 
separate bundles (Pl. 34. fig. 11), which, in connection with the bundles of the inner 
ridge, had branched off from the vascular system of the outer ridge and passed under 
the groove between the leaf-bundles. Transverse sections of the axis of the young 
inflorescence showed its bundles to be distributed in two more or less irregular whorls *. 
In the outer whorl there were several cases of three, four, or more bundles arranged 
to form a concentric group}. No transfusion-tissue was yet present, and the pith 
was parenchymatous. It was quite clear that all the bundles were entirely composed 
of secondary elements produced by the tangential divisions of the meristematic 
parenchyma (Pl. 35. fig. 21). 
It is interesting to notice that the bundles were better developed and the xylem more 
strongly lignified in the upper portion of the young inflorescence-axis. The bundles are 
therefore probably older in this region, a fact which would suggest that they develop 
first here and later become extended downwards. Similar facts were observed in the 
newly intercalated bundles in the young leaves. 
It will be seen from this account that the vascular system in the young ridges and 
inflorescences is entirely secondary in origin, all the bundles being derived from the 
growth and further extension of the small concentric ring of secondary bundles which 
arises first in the outer ridge and later supplies vascular tissue to the inner ridge and 
the inflorescences, 
Section IV.—THE CoryLEDONARY BUDS. 
h The young cotyledonary buds are composed entirely of parenchymatous tissue and 
ave at first no vascular supply. 
In the Stage represented pe PL. 34. fig. 2, numerous fibres are distributed throughout 
the tissue of the now flattened cotyledonary buds, and corky tissue has been developed 
at their pointed ends. Each bud receives a number of small vascular bundles arranged 
to form an elongated series, In Pl. 35. fig. 17 it can be seen that the end bundles of the 
series are collateral and much curved, having their xylems regularly orientated towards 
the rest of the bundles. The remainder are, on the contrary, very irregularly distribated 
and may be collateral or concentric. At the apex of the bud the bundles tend to become 
urse of publication by Sykes, in Phil. Trans. 
eseription of the adult inflorescen + Worsdell, 1901, p. 768. 
Roy, Soe, 1910 
