Wernham, The Systematic Anatomy of the genus Canephora. 
471 
C. madagascariensis, nor are the walls of the extra-stelar 
parenchyma-cells specially thickened near this bündle as 
in C. angustifolia. Tannin is not remarkably plentiful; 
a few large cluster-crystals of calcium oxalate are to be 
seen. 
b) Midrib. The shape in transyerse section is distinc- 
tive; the ventral surface is approximately flat, and there is 
a prominent dorsal rib. The primary xylem forms abroad 
band, and the wood-ring is ten to twelve vessels broad. 
The concavity of the bündle is occupied by a few thin- 
walled cells with large lurnina, and the ground tissue 
generally is of thin-walled, relatively large cells. 
c) Lamina. The leaf is comparatively thin, ofamore 
or less mesophilous type; palisade and spongy tissue are 
not clearly differentiated, bnt the lacunar System isrela, 
tively well - developed. The vascular bundles are small- 
with few fibres. Fairly large cluster-crystals of calcium 
oxalate are common. The stomata are not sunk; the guard- 
cells are flattened parallel with the leaf surface, and 
each is adjacent to a small subsidiary cell with thin walls. 
B. Anatomical Characters of the genus. 
These are, asis to expected from the general external 
habit of these plants, of a nature usually associated with 
xerophily. Thus, the parenchyma is for the most part of 
thick-w r alled elements; the intercellular space-system is 
inconspicuons, even in the leaves where the lacunae are 
bnt feebly developed; the epidermis in all parts is pro- 
vided with a remarkably thick cuticle; the fibres every- 
where have exceptionally thick walls, with lurnina almost 
or quite obliterated; the xylem vessels, too, are small as 
seen in section, and have small lurnina. 
A more or less continuous sclerenehymatous sheath, 
not improbably of pnloem-fibres, occurs immediately exter¬ 
nal to the phloem of the stem, comprising a single layer 
for the greater part of its circumference; no otlier defi¬ 
nite stereom is present. 
The petiole is traversed by three vascular bnndles — 
one large median Strand and two quite small lateral ones; 
the main bündle is cylindrical and hollow, the continuity 
of the cylinder being interrupted by a narrow gap on the 
ventral side. The main bündle of the midrib consists of 
a continuous cylinder of xylem surrounded by phloem. 
The leaf-blade is comparatively thick in all the 
species examined, although C. Goudotii shows some 
leaning to a thinner type. The guard-cells of the stomata 
are always associated each with a subsidiary cell placed 
