Pegg. — Ecological Study of New Zealand Sand-dune Plants. 171 



Leaves often appaar whorled, arising in opposite pairs,, or clusters of 

 two to four leaves, sometimes on small branches ; dull green, linear, 

 relatively thick, obtuse or subacute, \-\ in. long, ^"tb m - wide, mid-vein 

 apparent. Fruit, a white fleshy drupe, about \ in. long. 



(c.) Leaf -anatomy. Fig. 6. 



Epidermis of polygonal cells with rather thick walls and outline slightly 

 waved, cells seeming granular and to contain chloroplasts ; stomata very 

 frequent, enclosed in two epidermal cells, and rather prominent ; a thin 

 cuticle. Epidermis much the same on both surfaces. 



Chlorenchyma : Layers of palisadic cells on both surfaces, rather loosely 

 arranged, cells towards the middle much looser, with large intercellular 



Fig. 6. — Coprosma acerosa : Part of T.S. of leaf. 



spaces. Embedded in the chlorenchyma are several cells containing small 

 raphides (found, when tested, to be crystals of calcium oxalate). 



Fibro-vascular bundles : Five or six seen in transverse section, travers- 

 ing the mesophyll ; a mass of colourless parenchyma cells, probably for 

 water-storage, adjacent to the mid-vein, on the ventral surface ; bundles 

 well developed, a mass of xylem and a considerable amount of phloem ; 

 each bundle surrounded by a parenchyma sheath. 



(d.) Conclusion. 

 The almost isolateral leaf, strong development of palisade tissue, and 

 presence of water tissue are xerophytic characters ; otherwise the leaf is 

 mesophytic. Here, again, as in Calystegia Soldanella and Pimelea arenaria, 

 it seems that the habit of the plant rather than its structure fits it for its 

 exposed position on the active dune. 



