Wernham, The Systematic Anatomy of the genus Canephora. 471 



C. madagasco^riensis , nor are the walls of the extra-stelar 

 parenchyma-cells specially thiekened near this ?)uiidle 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 transverse soction is distinc- 

 tive; the ventral surface is approxiniately flat, and there is 

 a prominent dorsal rib. The primary xyJem 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 lumina, and the ground tissue 

 generally is of thin-walled, relatively large cells. 



c) Lamina. The leaf is comparatively thin, ofamore 

 or less niesophilous type; palisade and spongy tissue are 

 not clearly differentiated, but 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. Änatomical 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-walled elements; the intercellular space-.system is 

 inconspicuous, even in the leaves where the lacunae are 

 but feebly developed; the epidermis in all parts is pro- 

 vided with a remarkably thick cuticle; the fibres every- 

 where have exceptionally thick walls, with lumina almost 

 or quite obliterated; the xylem vessels, too, are small as 

 Seen in section, and have small lumina. 



A more or less continuous sclerenchymatous sheath, 

 not improbably of phloem-fibres, occurs immediately exter- 

 nal to the phloem of the stem, comprising a single layer 

 for the greater part of its circumference; no other defi- 

 nite stereom is present. 



The petiole is traversed by three vascular bundles — 

 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. Qoudotii shows some 

 leaning to a thinner type. The guard-cells of the stomata 

 are always associated each with a subsidiary cell placed 



