156 Transactions. 



Tlie cortex is a very narrow band of tissue, composed of small round 

 thick-walled cells which, contain tannin and which are closely packed 

 together, so that there are no air-spaces. 



The phloem also is a narrow band of tissue. The phloem parenchyma 

 cells contain tannin. The xylem is of the same type as in T). Urvilleanum. 

 In addition to the numerous u.niseriate medullary rays, there are 3 or 4 

 wide multiseriate rays. The cells of the latter do not have lignified walls, 

 but they contain tannin. There are more wood-fibres with thickened walls 

 in the wood of this [)lant than in D. Urvilleanum. 



The pith is solid and like that of D. Urvilleanum. except that tannin 

 is more abundant. 



24. Pentachondra pumila R. Br. 



Growlh-form. — This plant is a much and closely branched dwarf shrub, 



2-6 in. high ; stems stout, woody, and procumbent ; the branches are 



ascending, and are covered by a very dark-brown bark. The leaves are 



numerous, crowded, suberect, | in. long, oblong to ovate-oblong, and with 



a callous tip. 



Anatomy. 



Leaf (figs. 24-26). — In shape the transverse section is like that of the 

 leaf of Draco phijllum Urvilleanum, but in the latter the convex surface is 

 the lower, and in this plant it is the upper. 



The upper surface consists of large regular cells, which are slightly 

 elongated at right angles to the surface of the leaf. The lateral and internal 

 walls of these cells are thin, but the external walls are very much thickened. 

 In addition there is a very thick rough cuticle. The lower epidermis consists 

 of small regular cells. Their walls are only slightly thickened ; and there 

 is a thick cuticle, which is not, however, as thick as on the upper surface 

 of the leaf. Stomates are confined to the lower surface ; they are not 

 frequent. The guard-cells are at the same level as the other epidermal 

 cells, and their walls are only slightly thickened. The guard-cell ridges 

 are small. 



The chlorenchyma is differentiated. The palisade tissue consists of 

 2 layers of large typical palisade cells. Tlie spongy parenchyma consists 

 of smaller more or less irregular cells. All the mesophyll cells are thin- 

 wallecl. There are air-spaces between the cells in both the spongy and 

 the palisade tissue, but they are small. The cells contain numerous rather 

 small chloroplasts, and many contain tannin. Oil-drops are found in some 

 of the mesophyll cells and also in the cells of the upper epidermis. 



The vascular bundles are small, and the parenchyma of both the xylem 

 and the phloem contains tannin. Beneath each vascular bundle there is 

 a small mass of stereome, consisting of small cells with very thick walls. 



Stem (fig. 27). — The corky tissue forms a band of varying width ; the 

 cells are small, and have thick walls. 



The cortex is a moderately wide band of very regular oval cells, which 

 have thin walls and which contain tannin. This tissue has onlv verv small 

 intercellular air-spaces. 



The phloem, xylem, and medullary rays are the same as in Dracophyllum 

 Urvilleanum. The phloem parenchyma and the medullary rays contain 

 tannin. 



Scattered in the phloem and in the cortex there are more or less radial 

 lines of small cells with suberized walls. 



The pith is solid, and consists of large more or less polygonal cells with 

 thickened lignified walls. These cells contain tannin. 



