Wernham, The Systematic Aiiatomy of the genus Canephora. 



461 



The phloem is of one or two laycrs only. These are densely 

 packed with tannin and calcium Oxalate chiefly in the form of 

 crystal-sand. The phloem apparently surrounds the wood-cylinder 

 almost completely. The intra-xylary tissue consists for the most 

 part of cells with very thick walls, among- which groups of thin- 

 walled cells are interspersed, as in the stem. A certain aniount 

 of tannin and crystal-sand of calcium Oxalate occurs in this tissue. 



There is no continuous fibrous sheath in the midrib as in the 

 stem and petiole. A few fibres appear here and there, associated 

 with the main bündle, principally on the ventral side where they 

 form a broken series. 



The extra-stelar ground tissue is of more or less large paren- 

 chymatous cells, many with relatively thin walls. A number of 

 thick-walled elements also appear, especially in the neighbourhood 



Vq/vv^uA 



Fig. 5, c. 



Fig. 5. Diagrams of leaf-midrib in («) Canephora madagascariensis, 



(b) C. angiistifolia, (c) G. Goudotii, in transverse section. 



V. r. ventral rib ; d. r. dorsal rib ; other signs as in Fig. 3. 



of the bündle, where they doubtless take the place of a more 

 definite fibrous sheath; the latter we shall meet in the case of the 

 other two species. No definite sclereuchymatous fibrous tissue is 

 present in the ground tissue. Tannin is abundant in this ground 

 tissue, especially in the ventral rib. Crystal-sand of calcium Oxa- 

 late, more or less loosely aggregated, is faiiiy plentiful. 



The epidermis on both sides is similar to that of the stem, 

 but the cuticle is even thicker. 



c) Lamina. (Fig. 6, a) The leaf is relatively thick. The 

 palisade is clearly differentiated from the "spongy" tissue, but the 

 lacunar system in the latter is but feebly developed. 



A Single row of fibre-bundles appears at frequent intervals 

 in transverse section running in different directions in the inferior 



