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-covering more dense than the sandy shore, nor are special adaptations 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 Rumex neglectus(?), with its leaves flattened close to the ground, Ranunculus acaulis, Cotula muelleri, and an introduced
species of Trifolium. Within a few metres of high-water mark the strand, sloping upwards, gradually merges into the gently sloping peaty ground, which in some places is carpeted with grasses, and in others has small belts of Olearia traversii coming right down to the shore.
Just at the junction of shore and meadow is a turf of Selliera radicans, a plant with a slender stem creeping on or close to the surface of the ground, and with numerous short roots descending into the gravel; its thick leaves also are pressed close against the ground. That very curious umbelliferous plant, Crantzia lineata, also forms a turf in similar situations. Its rush-like hollow leaves are described by Asa Gray as “petioles in place of leaves” (22, p. 205), while Hooker, in the “Flora Antarctica” (30), speaking of specimens from the Plate River, remarks that the leaves sometimes expand into a plane linear-lanceolate obtuse lamina. Goebel calls attention to the same fact (21, pp. 45, 46), and shows clearly that the peculiar structure of Crantzia is a protection against drought, although the South American form grows in swampy meadows. How efficient such an adaptation is for xerophytic conditions, and yet how it can live also in hygrophytic stations, is well illustrated by the Chatham Island plant, which I collected in very wet swamps, on fairly dry sand dunes, on rocks by the sea exposed to frequent drenching with salt water, on extremely dry limestone rocks, and in the shade of the forest on moist peaty ground. Near New Brighton, Canterbury, New Zealand, it grows in a Phormium swamp on the bank of the River Avon, subject to some hours' immersion daily in water, which is often slightly brackish, and even at times extremely salt.
Growing near the rocks which jut out of the stony shore is Urtica australis, a very large nettle, which, as will be seen further on, forms thickets in some parts of the island. At Te Whakaru it is not very tall, being 30 cm. to 35 cm. in height, but the leaves measured 15 cm. by 10 cm. Its thick stems, 1.5 cm. in diameter, enable it to resist the wind. Here and there on the shore grows the introduced Plantago media, which is so much reduced in size and changed generally that it might easily be taken for a different species, were it not for examples of the type growing in a position more favourable for its development further inland.
No doubt a number of other plants occur as constituents of this formation, but none are mentioned in my notes. But, at any rate, the formation is distinctly a modified one, for not only have exotic plants invaded it, but it must have been much changed by sheep, since Te Whakaru was one of the first European settlements on the island.