The Anatomy of Matonia sarmentosa, Baker. 309 
approximate and eventually meet, whereby the central vascular 
cylinder again becomes independent of the solenostele. 
It is interesting to notice the occurrence of a definite 
“ Lindsaya ” structure 1 2 3 4 5 in connection with the node. In the region 
where the central cylinder fuses with the margin of the leaf-gap a 
very few (2—4) sieve-tubes appear in the centre of the axial stele 
(Fig. 6). As we pass forwards these sieve-tubes gradually approach 
one side of the xylem-cylinder, until eventually they unite with the 
general phloem of the exterior. The union occurs laterally, not at 
the dorsal point of fusion of the two cylinders, but at a point distant 
therefrom by about 90°. 
Pkotoxylem. 
The protoxylems of the stem are by no means so distinct as 
those of the petiole, but in the solenostele there appear to be about 
seven groups of small scalariform tracheids, opposed to slight 
centrifugal projections of the layer of sieve-tubes, but not producing 
marked crenulations in the outline of the xylem ring. At the 
departure of the leaf-trace three dorsal protoxylems pass off, and 
presumably are continuous with the three protoxylems of the 
petiolar bundle ; the actual connection, however, was not observed. 
In the central cylinder a group of unusually small scalariform 
tracheids was observed in the region of fullest fusion with the 
solenostele (Fig. 43). It is suggested that this may represent a 
rudimentary protoxylem. It is to be noticed that it appears at the 
same point as do the internal sieve-tubes—that is, at the point 
where the transition from protostele through the Lindsaya-type, to 
solenostele is taking place. 
In conclusion I wish to express my indebtedness to Professor 
Seward for placing the material at my disposal, and for valuable 
help in the work. 
1 See Tansley and Lulharn, Ann. Bot., XVI., p. 157, 1902. 
BIBLIOGRAPHY. 
1. Baker, J. G. Journ. Linn. Soc. (Bot.), XXIV., 1888. 
2. ,, ,, Ann. Bot., V., 1891. 
3. Bovver, F. O. The Origin of a Land Flora, London, 1908. 
4. Christ, H. Die Farnkrauter der Erde. Jena, 1897. 
5. Copeland, E. B. Philippine Journ. Sci. (Bot.), III., 190S. 
