Pegg. — Ecological Study of New Zealand Sand-dune Plants. 167 



This plant grew well when pot-grown in the greenhouse, seeming to 

 endure both moisture and dryness. Some shoots grew erect, others bent 

 over the sides of the pot and took root in the sand beneath. 



12. Epilobium nerterioides. , „ , ■ 



(u.) Habitat. 



Very common in moist sand-hollows at both ends of the beach. On 

 the south end it grew commonly with Selliera radicans, forming sparse 

 carpets on the surface of the sand. 



(b.) Growth-form. 



A small creeping herb, with stem covered, and only the leaves visible 

 above the sand in its natural habitat, forming a double row or small patch 

 of leaves dotted more or less closely over the sand. 



Stem long, creeping, often under sand, herbaceous, slender, giving rise 

 at intervals of about 5—5 in. to a pair of leaves and a rootlet or two. 



Lewes opposite, with short petioles, §— \ in. long, the blade orbicular 

 or orbicular-ovate, apex rounded, top b,?nt slightly downwards, margins 

 entire, green, glabrous, slightly fleshy. 



Capsule four-lobed, about £ in. long, on peduncle longer than the 

 capsule. 



(c.) Leaf-anatomy. 



Epidermis : On both surfaces walls thin, wavy outline ; stomata 

 numerous, irregularly arranged, prominent ; a few unicellular hairs occur, 

 with granular contents ; no cuticle. 



Chlorenchyma : On upper surface very large palisade cells ; on undersidi 

 spongy mesophyll, with large intercellular spaces. In section parallel to 

 surface chlorenchyma cells are circular, with large chlorophyll grains ar- 

 ranged round the walls ; crystals (raphides) commonly found embedded 

 in cells in the mesophyll. 



Fibro-vascular bundles few and small, consisting of a few xylem vessels, 

 spiral chiefly, and a small patch of phloem ; bundles surrounded by a 

 parenchyma sheath. 



(d.) Conclusion. 



Leaf-anatomy shows that this plant, like Epilobium Billardierianum, is 

 a strong mesophyte, although its prostrate habit appears xerophytic. The 

 plant is very variable in habit ; when grown in ordinary dry sand in the 

 greenhouse many shoots grew erect, and the leaves were longer and narrower 

 and of a darker green. Sections taken of these leaves which grew up into 

 the light showed that the cells are smaller and more numerous. 



13. Gunnera arenaria. . „ . . 



(a.) Habitat. 



Common in damp sand-hollows, towards north end of New Brighton 

 beach ; not found at south end. 



(b.) Growth-form. 



A small plant forming leafy patches or round mats often several feet 

 in diameter. Conspicuous when in fruit. 

 Rhizome stout, with withered leaf -bases. 



