The Anatomy of Matonia sarmentosa, Baker. 301 
formed from each cell. The cortex is composed of elongated thick- 
walled cells with simple pits. 
The endodermis is a thinner-walled single layer of cells with 
slight thickenings on the radial walls which break easily in cutting 
sections. Within this lies the single layer of thin-walled cells 
constituting the pericycle, which abuts directly on the proto¬ 
phloem. 
The vascular tissues in the internode consist of two concentric 
cylinders, the outer being solenostelic and the inner haplostelic. 
The histology of the tissues is closely similar to that described by 
Seward for M. pectinata : the whole structure is, however, on a 
somewhat smaller scale. The crenulations of the solenostelic 
cylinder are not so marked as in the outer cylinder of M. pectinata , 
but more closely resemble those in the second cylinder in Seward’s 
figure (9, pi. XVII., fig. 9). The general aspect of the transverse 
section of the internode is much like that of this figure if we 
imagine the outermost cylinder removed. 
The xylem of the outer cylinder is encased as usual by phloem, 
proto-phloem, pericycle and endodermis, both within and without. 
The axial xylem-strand is surrounded by the other typical stelar 
tissues in the same way. Between the two cylinders lies a zone of 
sclerenchyma of the same character as that constituting the cortex, 
but of small and variable thickness, being usually broader on the 
ventral than on the dorsal side. 
The sieve-tubes are of considerable diameter, and have rather 
thick walls which stain more intensely with methyl violet than do 
the tracheids. In this respect they differ from the sieve-tubes of 
the stem of M. pectinata, though in the petiole thick-walled sieve- 
tubes occur (cf. Seward, 9, pi. XIX., fig. 25). 
Bifurcation of the Rhizome. 
A series of sections was cut through the only bifurcation which 
was available, and the disposition of the tissues was observed to be 
as follows (Fig. 38):— 
Behind the fork there are present the two usual cylinders, 
lying quite free from one another. As we pass forwards to the 
fork the internal cylinder approaches the outer one and fuses with 
it by a broad junction in a dorso lateral position. At the same 
time the outer hollow cylinder becomes elliptical in transverse 
section. The junction between the two cylinders then narrows 
