342 Transactions. 



Young stems, the base of the stem, and to a less extent an older stem, show 

 the central medulla and medullary rays thickly set with starch. 



Engler has said that in Macropiper heckeria, Piper chavica, the bundles 

 are in rings, the outer bundles joined. In Macropiper excelsum the bundles 

 of the outer ring are separated by very wide medullary rays, as already 

 stated. Tangential sections can also be cut in which the medullary ray 

 is continuous right through. A portion of the internode of the woody 

 stem was boiled for some time in water, and the outer tissues stripped off. 

 The bundles showed only an occasional join. Some of the bundles could 

 be separated throughout almost the whole length of the piece, 2 in. There 

 is no network of anastomosing. A join is effected by a branch of very 



Fig. 5. Bundle from stem, showing xylein scattered : <i. phloem ; b, cambium , c, xylem. 



X 150. P. Endlicheri. 

 Fig. 6. Joining among central bundles in lowest internode seedling (see tig. 6a, 6). 



X 44. M. excelsum. 



few elements. A longitudinal face shows no anastomosing. Hence it 

 must be concluded that the outer ring of bundles in Macropiper excelsum, 

 at least, is only occasionally branched. Branching and forking of the 

 bundle takes place at the nodes. 



Peperom ia Endlich eri . 



Peperomia Endlicheri is a rock-plant, less often an epiphyte. Its stem 

 is succulent, its leaves store water. A cross-section through the stem 

 shows on the outside an epidermis of narrowish elements. The cortex is 

 succulent, and shows oil-sacs. The presence of oil is highly characteristic 

 of the Piperaceae. Here, as in Piperaceae generally, the oil-sac consists 

 merely of one of the cells of the cortex. Strasburger and De Bary both 

 make reference to the ethereal oil found in Pipers ; Engler says mucilage 

 passes in the epidermis and cortex, but the walls of the passages do not 

 differ from those of the cells around ; the contents give a pungent odour 

 to the plant. 



Scattered in the ground tissue of P. Endlicheri are bundles showing 

 an arrangement as in many Monocotyledons. But in Peperomia, as Engler 

 an others point out, the bundles have a cambium. In the New Zealand 

 Peperomia, however, the activity of the cambium is at a minimum The 

 amount of lignified tissue always remains small. There is no definite 

 arrangement in this species in rings ; whereas in some Peperomias there are 

 rings. In Peperomia qalioides there are two rings of five. 



