( Intraxylary) Phloem in the Stems of Dicotyledons . /. 573 
other cases, nearly half-way between the two rings, are smaller bundles 
possessing a very small amount of xylem. One of these bundles, as seen 
in a transverse section, taken near the node, had several xylem elements 
attached to the outer 1 side of its internal phloem. 
At the side of one of the bundles of the inner ring or series was seen a 
small isolated phloem-strand. This fact is important: it shows the occur¬ 
rence of phloem-strands which represent independent bundles; for this 
strand is obviously homologous with a small bundle, possessing a small 
amount of xylem, which was described in the last paragraph. It has thus, 
most probably, lost its xylem and is on the way to extinction. 
L. leucantha. 
Petiole . 
Besides the cylinder of normal bundles there are three quite small 
bundles, one of which, occurring in the ring of large bundles, possesses 
a little xylem. The remaining small strands, occurring in the pith, possess 
phloem only; if traced higher up, one of these latter is seen to fuse with the 
internal phloem of one of the bundles of the ring; the other two appear to 
die out above. In the highest part of the petiole, where the medullary 
cavity occurs, there is no sign of any of the small strands. These latter 
evidently represent an interior system or ring of vascular bundles. 
L. clavata. 
Peduncle. 
In the middle typical pait of the organ there is a central pith-cavity 
surrounded by an irregular, sinuous ring of bicollateral bundles, evidently 
formed by the radial congestion of two rings. A portion of one of the 
bundles has its internal phloem widely separated from the xylem and 
from the internal phloem of the major portion of the bundle; this medul¬ 
lary phloem-strand is thus quasi-independent. At the side of one of the 
ring-bundles, near the inner embouchement of the ray, is a very small 
normally-orientated vascular bundle. At the inner embouchement of 
another ray, and alongside the internal-phloem group of the adjoining 
ring-bundle, is a very small inverted vascular bundle. Its position and 
appearance suggest that it represents a fellow-strand of the internal phloem 
of the ring-bundle. This is supported by the fact that, attached to the 
outer side of the internal phloem of two or three of the ring-bundles, are 
from one to a few xylem elements . This is due to the fusion, at least in 
1 Wherever this term is used in the same connexion it has reference to the parts of the organ as 
a whole, not to those of the individual bundle. 
