Wernham, The Systematic Anatouiy of the gerius Ganephora. 459 



The xylem of the main bündle forms an almost unbroken 

 hollow cylinder, intorrupted only l)y a sniall ventral gap which 

 is almost completely blocked by sclereiichyniatous fibres. The wood 

 consists für the most part of sccondary vessels, four to five eiements 

 broad, in regulär radial arrangoment. As compared with the stem, 

 the wood in the petiole is comparatively loose in texture, being 

 intersected by several conspicuous parenchymatous inedullary rays, 

 in some cases three to four cells broad. At one or two points 

 these rays "fan out" (Fig. 3, a, 4, /') into patches of parenchyma; 

 this parenchyma has no crystal Contents. There are few or no 

 fibres in the xylem. 



The central tissue in the concavity of the xylem is composed 

 of cells rather large in section, with rather thick walls which show 

 signs of lignification. Tannin and calcium Oxalate are fairly 

 abundant, the latter in the form, principally, of cluster-crystals ; 

 crystal-sand, displaying a streng tendency to aggregation, also occurs. 



The phloem appears to be coextensive with the xylem, the 

 periphery of which it foUows as far as the edge of the gap. In 

 some parts the phloem is four to six cells broad, consisting of 

 sieve-tube tissue and parenchyma. Tannin and calcium Oxalate of 

 the nature already described are very abundant. 



The phloem is surrounded by an almost continuous sheath of 

 large conspicuous fibres with very thick walls (Fig. S, a; 4, sc), 

 many of them being radially elongated as seen in transverse sec- 

 tion. This petiolar sheath, and the nature of its elements, seems 

 to be characteristic for this species. 



The "concavity-tissue" is continuous through the gap with 

 the ground tissue in which the vascular system is imbedded. This 

 consists of thick-walled cells of varying size and shape, but there 

 is no definite sclerenchyma. Calcium Oxalate is very abundant as 

 crystal-sand aggregated into irregulär masses, with a few small 

 true cluster-crystals. Tannin is plentiful, especially in the outer 

 zone. 



The epidermis is similar to that of the stem; but no definite 

 hypodermis appears to be differentiated. 



The lateral vascular bundles consist chiefly of xylem arranged 

 in a fan of three or four rays of about three vessels in each ray, 

 the narrow part of the fan being ventrally situated; one or two 

 vessels, isolated from this main group, also appear. This xylem 

 is associated with a small amount of parenchyma, and one or two 

 elements which appear to be sieve-tubes, on the dorsal side. This 

 parenchyma contains crystal-sand of calcium Oxalate. 



The lateral bundles are associated also with a few fibres, 

 much of the type found in the neighbourhood of the median bündle. 

 These are situated for the most part dorsally, and in some cases 

 are radially elongated as seen in section. 



b) Midrib (Fig. 5,«). A large projecting rib (v.r.) runs 

 ventrally, the dorsal side being relatively flat and ungrooved. 



The vascular system consists of a main bündle from which 

 branches emerge to serve the secondary veins. The bulk of the 



