264 Transactions. — Botany. 



form an almost closed pipe, into which the dry air can with 

 difficulty penetrate. A transverse section of the leaf shows that 

 it is conduplicate, and appearing almost as if terete. The two 

 halves of the leaf are slightly asymmetrical. Between the 

 margins of the leaf is a very narrow opening, which leads into 

 a wider channel in which the midrib projects. On each side 

 of the midrib are one or two, perhaps more, lateral furrows 

 reaching more than halfway to the dorsal surface of the leaf. 

 The epidermis of the dorsal surface has a fairly thick cuticle 

 and three layers of cells ; that of the ventral surface consists 

 of one row of rounded cells with thin walls, a few of the cells 

 being drawn out into unicellular hairs. The stomata are 

 situated in the furrows, and the guard-cells are sunk below 

 the level of the epidermal cells. The other plants mentioned 

 above, excepting Sonchus grandifolius, are all common New 

 Zealand halophytes with thick leaves and much-creeping 

 underground stems. 



Besides the sand having blown on to ledges, it is often 

 drifted against the lower parts of rocks, and forms there a 

 plant-station which puts one in mind of some of the slopes of 

 fine limestone debris in the Southern Alps of the South Island 

 of New Zealand. In such unstable ground grows the ex- 

 tremely succulent Atriplex billardieri, while patches of Tillcea 

 moschata are abundant. 



Stony Sea- shore. 



The only locality where I examined this formation was 

 Te Whakaru. Unfortunately, my notes are so few that I can 

 only give very general and by no means exact details. So far 

 as I can remember, the shore at Te Whakaru varies from large 

 loose slabs of stone piled one upon another to coarse gravelly 

 sand, containing large quantities of broken shells and having 

 very many rocks rising out of it. Such a shore is much more 

 stable than the dry sandy one before described; the presence 

 of stones on the surface helps to conserve the moisture, so 

 offering permanently moist spots for the ramification of roots, 

 and the large rocks afford shade and shelter. In consequence 

 of these altogether more hospitable edaphic conditions, the 

 stony shore formation is richer in species and its plant-cover- 

 ing more dense than the sandy shore, nor are special adapta- 

 tions against shifting sand or such strongly marked xerophytic 

 structure indispensable. All the same, the rich development 

 of the underground stem and lowly habit of growth to be 

 found in all the species — Urtica australis excepted — fits them 

 both for resisting drought and the attacks of sheep. 



Growing on the sand close to high-water mark are Bumex 

 neglectus(7), with its leaves flattened close to the ground, 

 Ranunculus acaulis, Cotula muelleri, and an introduced 



