256 Browne.—A Second Contribution to our Knowledge of the 
parenchymatous humps. In the smaller hump the bundles never form 
a continuous circle, and there is a gap adaxially, involving about one 
quarter of the circumference. At the level of insertion of the adaxial 
strands of this smaller branch on the two bundles of the main stele the latter 
bundles become temporarily united to one another by a narrow band of 
reticulate tracheides, resembling the elements of the nodal or supranodal 
xylem. All the other bundles of the main stem as well as the abaxial 
bundles of the branch stele remain throughout in a typically internodal 
condition, while the daughter and granddaughter bundles of the strands 
that showed reticulate tracheides—viz. the adaxial bundles of the branch 
stele—become typically internodal soon after entering the parenchymatous 
hump. As regards the larger abortive branch its abaxial bundles and 
all the bundles of the main stem at the level of insertion of abaxial and 
adaxial bundles retain a typically internodal structure. But the three 
adaxial bundles of the branch stele themselves develop a few reticulate 
tracheides; these soon die out and are never sufficiently numerous to unite 
any of the bundles laterally to one another. 
The four strands that are given off by the main stem to form, after 
subsequent division of two of their number, the six adaxial bundles of 
the larger abortive branch give off, before this second division, four traces 
pointing more or less straight adaxially towards the bundles of the main 
stem. At a lower level these enter a sheath inserted at the lower point of 
junction of stem and hump. This sheath surrounds the adaxial half of the 
hump, and is in reality inserted obliquely in the angle between it and the 
main stem. Its connexion with the latter ceases higher up than (i. e. owing 
to the inversion of the branch, before) its connexion with the hump, and as its 
traces are derived from the bundles of the branch stele it may be regarded 
as belonging to the abortive branch, though it is curious that it should occur 
not on the free but on the adaxial side of the latter. A similar, smaller 
sheath, containing three bundles, occurs ki connexion with the small abortive 
branch, and is here found, as we should expect, on the abaxial side of the 
hump. Its traces, however, pass out obliquely from the adaxial bundles, 
before these have divided a second time, and whilst they are therefore two 
in number. Both bundles give off traces at approximately the same level, 
and these diverge into the sheath from different sides of the hump; later 
(i. e. lower) one of the two gives off another trace. All these traces actually 
pass steeply downwards and outwards, but in view of the inversion of the 
abortive branch they are passing organically upwards and outwards. 
Normal Nodes of the Fertile and Sterile Stems. 
The uppermost vegetative whorl of the stem bearing Cone D was 
quite normal. There were thirty-six bundles in the internode above 
and below it, and thirty-six traces were given off. Vertically above the 
