448 MR WM. T. GORDON 



occupied a definite position also in the middle cortex. The whole zone of middle 

 cortex in a stem 25 mm. diameter is a ring 2 - 3 mm. in thickness, and shows no trace of 

 secondary growth. In none of the specimens examined can any secondary growth be 

 seen in this middle cortex. 



External to the middle cortex comes a belt, two to three cells broad, of tangentially 

 elono-ated elements with thin walls ; these are the inner cells of the outer cortex. These 

 innermost cells are no larger than those of the middle cortex, but they gradually give 

 place to larger cells with thicker walls. The tissue in this region and all the more 

 external parts is in most cases well preserved. The outer cortex can be divided into 

 three zones, of which the inner is composed of parenchymatous elements in no definite 

 arrangement. Here again, however, patches of tissue filled with dark brown contents 

 may be observed. They are seen here to occur in places well removed from the out- 

 going vascular bundles and also from the outer and inner edges of the parenchyma. It 

 would seem, therefore, either that the cells secreted a resinous substance, or that they 

 acted as storage tissue and that the brown substance represents the stored food. The 

 inner zone stops just where the radial arrangement of the outer cortex begins, i.e. five or 

 six cells in from the periderm. The brown patches are therefore confined to the area 

 where there is no secondary growth. Beyond this, in young branches and in older ones 

 which have no periderm, the leaf-bases would be found ; in all the specimens examined, 

 however, some secondary cortex existed. Sometimes very little appears, but in other 

 cases there is a succession of periderm layers, denoting some sort of periodic rest and 

 active growth (fig. 8, pd.). 



The secondary cortex is formed by the rapid division of a belt of cells, near the out- 

 side of the primitive outer cortex. The resulting tissue is arranged in radial rows, and 

 is more regularly arranged in vertical rows than the surrounding cortical parenchyma. 

 Passing further out they become much elongated vertically, and in this species are filled 

 with dark material. I cannot see any trace of secretory passages in this species, though 

 they have been observed in others. 



The dark belt is succeeded externally by long clear cells, which in turn give place to 

 another dark zone like the last. In my specimens I cannot trace more than two of such 

 zones, but their presence seems to indicate some sort of periodic rest. Outside the last 

 dark peridermic ring, the cells are still radially arranged and vertically elongated, while 

 some rows are at the same time tangentially elongated. The last two or three layers of 

 this tissue become parenchymatous, and on this third cortical zone the leaf- bases abut. 

 There is no distinct abscission layer, but, when the leaf-bases are absent, they have torn 

 away this parenchyma, thus exposing the elongated elements of the secondary cortex on 

 the denuded stem. The leaf- bases persisted even after the upper portion of the leaves 

 had decayed, and on the shape of these leaf-bases specific characters are more safely 

 founded than on other parts of the vegetative tissue. 



Dr Kidston has shown in Lepidophloios that these leaf-bases pointed upwards on 

 young twigs, and outwards and even downwards on older ones, thus indicating that these 



