468 Wernham, The Systematic Anatomy of the genus Canephora. 



is similar to the external ground-tissue; the cells are more or less 

 circular in section, with rather thickwalls. There is, however, no 

 special thickening of the cell-walls in the neighbourhood of the 

 median bündle, such as we have observed in C. angustifolia. Cal- 

 cium Oxalate is abundant throughout the parenchymatous tissue; 

 its mode of occurrence is essentially similar to that in the last- 

 named species. There is a marked tendency for the crystal-sand 

 to become aggregated, and a few quite large Cluster crystals occur. 

 Tannin is not very plentiful; most of it appears in a sub-epidermal 

 band of four or. five cell-layers. 



The epidermis presents no special features, except that the 

 cuticle is appreciably thinner than in the previous species. 



The lateral bundles consist each of some fifteen to twenty 

 vessels, with but little associated parenchyma. This group, moreover, 

 is surrounded by a discontinuous set of large fibres, disposed more 

 or less regularly. 



b) MidrilD (Fig. 5, c). The shape in transverse section is 

 distinctive; as compared with the other species the ventral side is 

 flat, approximately flush with the lamina. Dorsall}^ the section 

 presents a very prominent rib, of furrowed and folded outline. 



The main vascular bündle occupies the greater part of the 

 sectional area. The xylem forms a broad ring, the secondary 

 elements presenting a regulär radial arrangement and extending 

 over about one half of the breadth; the primary wood is a con- 

 spicuous feature in the midrib of this species. The vessels are 

 small and much more numerous than in either of the other two 

 species, the xylem-band being from ten to twelve vessels broad. 

 The flbrous System of the wood is similar to that of C. angustifolia^ 

 but there are more fibres towards the inner side of the ring than 

 in that species, particularly in the ventral region. The medullary 

 rays are very few in number, and impregnated with tannin. 



The phloem is represented by a narrow band, densely packed 

 with tannin; calcium Oxalate also abounds, in the form of aggregations 

 of crystal sand. The intra-xylary ground parenchyma consists of a 

 few very large cells with thin walls; neither tannin nor calcium 

 Oxalate is plentiful in this tissue — the latter occurring in small 

 sand-masses. The same applies to the extra-stelar ground tissue, 

 except that the cells are not so large; here the tannin is conflned 

 for the most part to one or two layers immediately subjacent to 

 the epidermis. The main bündle, and the brauch bundles also, are 

 surrounded each by a well-marked sclerotic sheath of one layer 

 of small fibres; these are rather loosely arranged. 



The Upper and lower epidermal surfaces are similar, of small 

 Square cells, much as in C. madagascariensis ; the cuticle is, however, 

 relatively thin. 



c) Lamina (Fig. 6, c). The blade may be described as sub- 

 membranous, being of a thinner type than in the other two species 

 described. Palisade and spongy tissue are not clearly differentiated; 

 the former comprises two or three layers of cells rather smaller 

 and richer in tannin than the underlying layers. The cell-walls 



