(A) Henga Reserve

This is situated immediately behind the Chatham Lodge, where we stayed, on old sand dunes leading to the sea. It was at the fringes of the forest that I had my first close look at Chatham Island plants. I recognised a Myrsine, (M. chathamica), with fairly broad, but short leaves often notched at the tip. This species is also reported to occur on Stewart Island. There was also a Melicytus (M. chatamica) locally called mahoe, but quite distinct from ours. The leaves are fairly thick, flat and stiff in texture with prominent teeth. A common twining vine puzzled me for a while until I realised that it was Muehlenbeckia australia, although it is more robust and has much larger leaves than our version. The karakas seemed no different from ours, but a Coprosma (C. chathamica) was a big surprise. The exposed leaves are quite small and rolled after the fashion of taupata, although unlike those of the latter they are not very shiny., However, the remarkable thing is that this Coprosma is a tree up to 15 m tall with a trunk sometimes more than half a metre in diameter!¹ (Fig. 2). It must surely be the biggest species of the genus. The trunk often has a pinkish tinge and has a hammer mark pattern something after the fashion of matai. Another distinctive feature of this species, is that it has broad juvenile leaves that are much larger than those of the adult (Fig. 3). Furthermore, as well as having small pits or cavities (domatia) on the undersides where secondary veins meet the midrib, as is usual in Coprosma, these leaves also have domatia scattered over the entire leaf undersurface, at junctions of higher order veins. I have seen this in some leaves of taupata (C. repens), although scattered domatia are not so frequent in this case.

Going into the bush I observed that karakas, although large, were scattered and that the commonest tree appeared to be Myrsine. The latter has trunks up to about 40 cm diameter, some of which have one or more peculiar collars of protuberant corky tissue contrasting with the general smoothness of the rest of the trunks. Scattered trunks of the Coprosma were also seen. In the undergrowth, kawakawa (Macropiper excelsum) caught the eye, the leaves seeming larger than ours and notable for not having holes eaten into them. The commonest undershrubs however were saplings of the Melicytus up to about head height. I was told that these established after the fences were erected. Looping stems of Muehlenbeckia were common but I saw no supplejack. Unexpected too was the absence of ferns, apart from the epiphytic Pyrrosia. Perhaps the sandy forest floor is not suitable for ferns and instead supports a lush growth of the so-called New Zealand spinach — Tetragonia tetragonioides. Further towards the beach the forest became lower and more windswept with Myrine becoming even more abundant. Emerging from the forest we found the first sand dunes were covered with a luxuriant growth of introduced grasses, but nearer the sea there was more open sand and more native species including Pimelea arenaria, Cyathodes parviflora with white berries, Coprosma acerosa and grey patches of the endemic Geranium traversii in the sand (all that I saw had white flowers in contrast to the pink flowers of the cultivated form). The Coprosma looked rather different from ours, being of a darkish hue and not forming tangled masses, but having its branches pressed closely against the sand. The beach was an impressive page 27 sight, sweeping northwards along Petre Bay and, apart from us, completely deserted. All the beaches we saw in the Chathams had fine white sand and this combined with the pale blue sea and white breakers gave quite a tropical effect, unfortunately belied by the coolness of the air.

(B) Motuhau Point

This is located on the western shore of the southern part of the lagoon where there are good rock carvings on an overhang of the limestone cliffs. The cliffs support a variety of trees and shrubs including the tree coprosma and Myrsine chathamica, as well as the Chatham lancewood, Pseudopanax chathamicus, and kowhai, Sophora microphylla.

The Chatham lancewood has a juvenile form but it is not as distinctive as its namesake on the mainland (Fig. 4). The juvenile is unbranched for some years with leaves that are quite broad but longer than those of the adult and not deflexed. They have a few coarse teeth distally while my observations suggest that the fully adult leaf is broadly rounded at the tip and without teeth. The adult tree has a freely branched, rounded crown (Fig. 5).

The kowhai is restricted to limestone on the Chathams and doesn't have the small-leaved rather chaotically branched juvenile frequently developed by the mainland form. A notable shrub was the bushy, greyish-green Hebe dieffenbachii, one of the three endemic hebes.

Where the beach abuts the cliffs there were a number of good sized trees of Olearia traversii (Fig. 6), in many cases with their shaggy-barked trunks steeply inclined towards the lagoon. The water of the lagoon tasted quite salty and there is salt marsh in places, with familiar mainland species. The beach is whitish with many shells and a prominent plant is the large dark-green nettle Urtica australis (Fig. 7). The species was new to us but it is found elsewhere in the subantarctic islands, Stewart Island and Fiordland. Unlike the shrubby Urtica ferox, on the mainland, this species does not have visible stinging hairs, but they soon revealed their presence when I tried to collect a specimen. My fingers tingled for several days afterwards.

The following day we headed for the north-east point of the island at Point Munning but stopped first at:

(C) Blind Jim's Creek

This is also on the western shore of the lagoon but in its northern part. Dedicated searchers were able to find a few fossil shark's teeth among the shells of the beach. The limestone cliffs supported some of the same species observed on the previous day, but in addition we saw a few plants of Geranium traversii and the New Zealand linen flax Linum monogynum, with pale blue, not white, flowers. There were also several clumps of New Zealand flax, Phormium tenax. This species occurs also along streams and around lakes and was formerly much more common. It is rather different from the common form in New Zealand. It is pale green with very broad, but not particularly long, leaves and the seed capsules are short and tubby.

From here we drove to the north-eastern peninsula via the narrow strip of sand separating the northern edge of the lagoon from the open sea. We called first at the Wiesner farmhouse which is notable for the remains of a Sunderland flying boat which crashed nearby many years ago, but also notable botanically for a private bush reserve.

(D) Wiesner's Bush Reserve

Here we saw a number of nikau palms (Rhopalostylis sapida). The ribbonwood (Plagianthus regius) was abundant along the path through the reserve. Unlike mainland plants, the Chatham ribbonwood does not have a divaricating juvenile with small leaves varying in size and shape. However, the leaves of young plants page 28 are much smaller than the adults, although similar in shape. Some very large karakas were present as well as small Myrsine chathamica and an undergrowth of particularly large kawakawas (Macropiper) and young Melicytus.

We continued on to Point Munning which has also been partly fenced by the Wiesners.

(E) Point Munning Reserve

Here the special interest is a seal colony. The surrounding schist rocks support a diverse flora of fleshy-leaved plants in peaty crevices, including the endemic fern Asplenium chathamense and Senecio radiolatus. Phormium is abundant behind the rocks. The nearby Te Whakaru island, which we did not visit, is connected at low tide and still has vigorous Myosotidium and Embergeria among washed up shells behind small beaches. On the slopes above the point there is an area of shrubs, partly protected by a Phormium “hedge”, which appeared to be a pure association of the endemic Corokia macrocarpa. Our next stop was

(F) Kaingaroa Beach Reserve

This was where the first Europeans, led by Lieutenant Broughton of Vancouver's expedition, landed and claimed the island in 1791 and named it after the Earl of Chatham.

To get to the beach one has to go through the Kaingaroa township's rubbish tip to an area of the beach that was fenced about 1939. Here there is a good colony of the robust sand binding sedge pingao (Desmoschoenus spiralis), its orange-green tufts of leaves looking decidedly handsome against the white sand of the dunes. Associated with it were vigorous clumps of the giant sow thistle Embergeria in flower and seed. The flowers are several cm across and grade from pale purple on the outside to pale yellow at the centre (Fig. 10).

(G) Kaingaroa Point Reserve

This is approached through Kaingaroa township where we noted some robust plants of Embergeria near houses. The reserve includes the former rubbish tip and sandy flat areas behind the coastal rocks supported a few embergerias and myosotidiums, but the most notable feature was a mat of prostrate Hebe chathamica in full flower. This species also grows on coastal cliffs, where it has a draping growth habit. If we had done our background reading more thoroughly, we would have gone a little further on to where a few plants of the endemic Leptinella (Cotula) featherstonii still grow among bird burrows.

We also paid a visit to the seacliffs at Matarakau further east on the norther side of the peninsula.

(H) Matarakau

Even here, on level surfaces, there is a layer of peaty soil and it is probably such soil, on ledges and in crevices of the cliffs, that results in the abundance of herbaceous plants. This is particularly the case with the endemic ice plant, Disphyma papillatum, with its attractive pink flowers, which forms draping massed down the cliffs.

(I) Hapupu Bush Reserve

This was our last stop of a busy but interesting day. Here are found the famous Moriori bark drawings or dendroglyphs on karaka trunks (Fig. 9). Many large karakas dominate this forest, with a few myrsines as well contributing to the canopy. Since the fence was constructed there has been abundant regeneration of young Melicytus in places. No Macropiper and no vines were noted and again ferns were rare. Going towards the sea the karakas diminished and low Myrsine became more common. In open places, Pratia arenaria was abundant on the sandy ground.

Hapupu Bush is located part way down the eastern side of the lagoon near the old airstrip. Passengers were driven in trucks across a shallow part of the lagoon to the Waitangi side!

(J) Nikau Forest Reserve

This, our first stop on the next day, is about a kilometre from the north-western shore of the lagoon. There is quite a large grove of tall nikau palms on one side of the bush (Fig. 10) with draping lichen on some of the trunks as an indication of the moistness of the climate. The main part of the forest is dominated by large karakas with some adult Pseudopanax and Coprosma. Melicytus and Myrsine are uncommon as is the undershrub Macropiper. Unlike the earlier forest visited, the abundantly regenerating tree in the undergrowth is Pseudopanax rather than Melicytus.

Both supplejack (Ripogonum) and Muehlenbeckia are common vines. The former had both flowers and fruits. Phymatodes diversifolius, Asplenium polyodon and an Earina occurred as epiphytes even on a few nikaus (Fig. 11). The Earina was flowering abundantly and the flowers were right for E. mucronata, but the leaves and stems seemed much too short for that species. The plant would match the description for Earina aestivalis, a species which has not been accepted for some time. Some of the earinas in this forest were longer stemmed than the majority and we later saw much longer specimens in southern forests also in full flower. So this poses something of a puzzle.

There were a few Dicksonia squarrosa tree ferns in places, so with the epiphytic species, ferns were somewhat better represented in this forest.

(K) Lake Kaimomi Reserve

This is near the north-eastern shore of the lagoon and is a good example of bog vegetation (Fig. 12). Large hummocks of the bamboo rush Sporadanthus traversii are conspicuous with their long, slender and closely aggregated, apparently leafless stems. This important peat forming species also used to be common in the Waikato bogs, but is now becoming rare there. Other important species are the purple flowered shrub Olearia semi-dentata, the needle-leaved shrubs Dracophyllum squarrosum, Cyathodes parviflora and Coprosma propinqua var. martinii (this and C. acerosa are the only divaricate species on the Chathams). In more open places Gentiana chathamica was in full flower. Phormium was conspicuous around the lake margins as well as the strange sedge Carex sectoides raised above the water on stout “trunks” built up from its own dead leaves and roots over many years. Carex secta on the mainland has a similar form.

(L) Wharekauri coast

This is on the northern side of the north-western peninsula where, contrasting with the white sand of the beach, there is an outcrop of dark basalt. The seaward side of this has a heavy fringe of that most impressive brown seaweed, the bull kelp (Durvillea antarctica), its massive fronds heaving and swirling in endlessly changing patterns in the heavy surf. The bull kelp is a prominent feature of rocky Chatham coasts.

(M) Basalt Columns

These are located on the southern side of the north-western peninsula. The approach is through extensive white sand dunes frequently capped by bushy shrubs of Pimelea arenaria. There are also a number of large Olearia traversii trees, some of which have been blown horizontal but are still growing. The stream flowing through the sand is stained brown by peat and again rock crevices near the sea are well stocked with salt tolerant plants. The more or less vertical, hexagonal columns, that formed as the basalt cooled, are an intriguing sight and comprise a reef and an adjacent shelf and cliff.

Two further forest localities were visited in the centre and north of the main island.

(N) Cape Pattison Reserves

Cape Pattison is towards the end of the north-western peninsula on the northern side. We drove along the western beach, then walked alongside a stream to the first reserve, which was fenced only a few years ago. As a consequence the forest floor is still quite open. The dominant trees are large karaka and Coprosma chathamica and smaller myrsines. Muehlenbeckie and supplejack vines are also quite common. Here we saw a sleeping possum under a hollow log — a signal reminder that this herbivorous pest is also established on the Chathams. Continuing out of the reserve towards the beach on the other side of the peninsula, there is first a grassy area, then a second fenced reserve, enclosing a rather battered example of coastal Olearia traversii forest. It is hoped that this will regenerate to provide a good example of this distinctive forest type.

(O) Plum Tree

This is on the western shore of the southern part of the lagoon. The trees here were the tallest we saw, with a mixture of karakas and coprosmas with massive trunks. In a hollow there was a grove of quite large ribbonwoods. On limestone outcrops near the shore we also found the small herb Colobanthus muelleri, of special interest to Barry Sneddon.

Unfortunately this forest is not yet reserved and as a consequence it is open and grassy underneath.