NEW ZEALAND PLANTS AND THEIR STORY.

Evening Star, Issue 12805, 5 May 1906, Page 11

NEW ZEALAND PLANTS AND THEIR STORY.

(By Dr L. Cockaysk, Cor. F.B.S. Ed.] (Copyright.) m. Nov Zealand Forests in Geperal.—Adaptation of Forest Plant? —Effects of Liglu nod Water.—The Relation of Sort——Flowers ar.d Fruits.—About OurTimters —The Fined, the Kowhai, and tfie PujirL—Variations of Triibers, according to Soil a.id Altitude.—The Colony s Timber Suppjv.—Our Ferula—the'K* eri, mixed, the Kahikaten, or White Pine, the Beech. However little llu< average colonigt may know about the plants of New Zealand, few there are who cannot raise some enthusiasm regarding th« "bush," as the forest is eviiywheio called. To joung and old it is a delight; the stately trees, the birds, fearless of man, and, above all, the wealth of ferns appal to ail. Hut that this forest is a unique production of Nature, found in no other land, is not a matter of ccirmon knowledge, though really it has many dairies to bo considered une of our priceless possessions. According to tho famojß plant-geographer, Schlinper, New Zealand his a rain-forest climate. That is to 6ay. it' no inhibitory conditions existed, une green mantle of forest would cover the vbote land Although this is not the case at present, it was in part so when the Burly settlors a'rived. But this great forest was" not all of one kind. The need of timber for house-bnilding soon showed tlmt various kinds of trees were more abundant in one locality than in another, ard that some were wanting in one forest which were plentiful elsewhere. As the trees had in 3!any ca--*>e Maori names, th<.' settlers soon learnt (in a rough manner, it is true) something as to the composition of the forests and their distribution. But, sis some Maori names are used very loosely, accuracy was puite impossible, rher-'fore, in these articles, although they are written entirely for the non-botanical reader, tho scientific names, which are definite, are used, as well as their more popular equivalents. There are two distinct classes of our forests—viz., those consisting of many different species : of trees, and those which arc formed of ono j kind of tree alone, or nearly so. To the ; first category belong most of the lowland ■ forests, with one or two exceptions; and i to the latter the upland and sub-alpine | beech forests and the swamp ' forests of ; KaLikaten. Let us (onsider first the ordinary mixed forests, the " bush " par excellence. These differ so much in their composition as to really constitute different societies, but all have much in common. —General Characteristics of tiio Mixed Forest.— The trees, with one or two exceptions, arc evergreen, and consist of many specks | .belonging to diverse families. Frequnetly the bases of the trunks develop plank-like buttresses, and their uppenro trots stretch over the forest iloor, half-buried, or at times raised high above the ground. Such rcots and bases of the trees are closely covered with mosses and liverworts. In their interstices humus lodges, in which many ferns and seedling plants find a fitting homo, The forest is made up of different lavers, if we consider tile level of the foliage. "The tall trees form the uppermost layer, the smaller trees and tallest shrubs tho second, smaller shrubs, tree-ferns, and juvenile trees the third, and finally comes the forest floor with its carpet of"mosses, liverwort, and filmy ferns, through which grow the smaller "ferns and herbs. A most important feature of the forest is the climbing plants or lianos, which rope-like hang from tho tree tops, form an impenetrable tangle or gracefully entwine A' -nialW trees and shrubs. 'Free fern*, sometimes 20ft or 30ft in height, with enormous feathery leaves, like giant umbrellas, frequently occur, often in groups and proves. Clost-grcwirg. small-leaved shrubs of dense habit form thickets. On tree-fern stems, fallen trees and even the forest floor

are sheets of delicate filmy ferns. Lichens of great size, white or golden or dusky, abound. Perched high up in the forest roof, in the forks of the branches, are birds' r.cst-like massed, several feet in circumference, of a plant of tlie,lily family (kahakaha, Astelia Solandri). Long frouds of feres and lycopods several feet in length hang drooping from the boughs, and certain orchids, with aerial roots and shrubs of various lands, too, grow h'gh on oth;r trees, which thus are turned into veritable gardens. In some few cases the flowers of a tree ate produced on the thick branches, and not. as- usual', from amongst the leaves. Now, should a botaci-t. knowing nothing of New Zealand, read this description, he would at once conclude it was no account of the forest of a temperate climate, but of one in the tropics. And this is quite true, tho common forest of New Zealand must be classed with the tropical, not with the temperate, forests. —Origin of Special Forest Plants.— The forest also tells us a gcod deal about the evolution of the wcnden'ul adaptations of certain plants to forest life On walking through its fastnesses one cannot fail to notice the subdued light, which is &«> tnech less than in the open. Above all things, most plants require sunlight; without th>6 they cannot manufacture in their leaf laboratories their necessary food from the carbonic acid of the air. In a forest, then, there must be a struggle for the sunlight. The tall trees meet the difficulty by raising their tops high into -the- heavens. But with the .-mailer plants it is another matter, and there must either become attuned to a mimimum of light or make some special effort to get their fair share. Consequently we find a spindly habit of growth in many youag forest trees—long, straight, thin stems, and few Literal branches—- " drawn up to the light" is the gardener's phrase. Cany cut this idea, a Yhtle further, and you have certain plants putting out long snoots, which, too weak to stand alone, lean against other trees for support. <Jo a little further still, and such long shoots develop certain organs to assist them to cLng to the supporting tree. So, by slow degrees, modification after modification arises for this end, until the wonderful family of liar.es is evolved, whose roots ran enjoy the cool and rich soil of the forest floor, but whose crowns dispute with the tree tops for the light of heaven, and under its influence bring forth their flowers, ripen their fruits, and manufacture stores of iood within their green leaves. Lianes may be conveniently divided into scramblers. root-climbers, twiners, mid ten-dril-climbers. Of scramblers, the various species of Itubus are excellent examples. These have developed those 6pecial curved hooks for climbing purposes which have earned for them the appropriate name of "lawyer.'' The various species of climbing ratas are root-climbers, such as MetrcEitleros florida (tho aka), M. hypericifolia, M. .-eandena (the aka). Many ferns also belong to tin's class—e.g.. Polypodiuni Billard.eii (the paretao), Loinatia. fiiliformis (the panako, tawhar.Au). Tho supplejack (Rhipogonum scandens, karaeo) and two plants allied to the common dock, Muehlenbeckja. australis and M. coinplexa, are very common .twiners. Finally, the various species of clematis and the Xew Zealand passion flower (Tetrapathaea australis, tho kcliia) are some of the tendril-climbers. Another method of seeking the light is to boldly leave the ground and perch high on the trees. Most instructive transitions between this perching habit and the normal may be observed in any New Zealand forest. The perching lilies (Astelia) also grow on rocks or form huge clumps on the ground. Many ferns live indifferently either on trees or the forest floor; so doss the lovely shrubby groundsel (Senecio Kirkii). Seedling trees are very common as perching plants, and some of the forest giants begin their career in th's manner, finally putting down roots to the ground, which grow into a solid '•root-trunk," the foimer host locked in their embrace and stifled. The northern rata (Mctrosidtros robusta) and the tree heath of the Chathams ((Dracopbyllum aibureum) frequently behave in this most ungrateful manner. Though many plants are eager to get into the fresh air and sunlight, others are the reverse, and have developed d'fferent adaptations in accord with other The' interior of a. thick forest has an atmosphere charged witu vapor not altogeiher tJUike fcfaat of a.glasshouse. Plants living.,.

under such conditions axe subject to much the same environment as submerged water plants, mi have developed similar leaves, which are so thin as to be able to absorb any water which may lall upon their surfaces. Such, amojigst others, are tlie filmy ferns (species of Hymenophyllurn and Trichoroanes), the beautiful crape fern <Todaßa supernal„ and its relative Todse* hyraenophylloides. Plants like these can only exist in "a moist atmosphere, and soon die when removed from their forest home. Many mosses and liverworts also belong to this "category, and mimic in their forms the smaller ferns, to which, of course, they bear no relationship. —The Flowers of the Forest.— New Zealand forests (ire not distinguished for their brilliant flowers. On the contrary, most are inconspicuous and of a dull color. But there are some notable exceptions. The northern and southern rataa bear multitudes of crimson blossoms. The yellow kowhai (Sophora grandiflora S. micropbylla) has been fitly termed the New Zealand laburnum. The various species of trees known as lacebark (Hoheria populnea, H. sexstylosa, and H. angustifolia) are, in their season, dense masses of snowy flowerß. Pennantia corymbosa (the kaikomako) vies in its purity with any bridal flower. The putaputaweta (Carpodetus serratus) is a rival of the English jn;<y. The tawiri (Ixerba brexioides) of the Auckland upkud forest is so showy that the Maoris had a special name, whakou, for its blooms. The tree manuka {Leptospormum ericoides), with its multitude of white or pinkish flowers, quite equals tile popular Spiraea Tliunbergi of gardens. —The Fertilisation of the Flowers.— The question of how flowers are fertilised is of high in.erost, and for the p.ut half-century has received much attention. Space forbids but a brief mention here. Flowering plants have two special organs for purposes of fertilisation. The stain n and the pistil- The former ptodu.es a yellow "dust," the pollen; the Litttr contains within a little chamber o.e or more egglike bodies, the ovules. Each ovule contains in its interior what may be called an "e:'s" If tho pollen falls upon that part of the pistil termed the stigma at the right time, a union will take place between some of the ts-sential part of the pollen and the eg'*. This will lead to the formation of an embryonic plant within the ovule, which, when the embryo is fully developed, is

termed the seed. In some instances the stamens and pistil are close together on the same flower, and pollen and stigma are readv the one for the other at the same time" in which case the flower can fertilise itself. But in a considerable number of instances self-fertilisatiun is impes ible, and the pollen of one plant or flower must be applied to ths stigma of another. Such cross-fertilisation, as it is called, is proved to be beneficial for many plants. A large percentage of New Zealand trees and shrubs have the .pollen-bearing flower on the one plant and the ovule-bearing on another. Others, again, are so constructed that the pollen is ripe before the stigma of the same flower is ready to receive it, or the stigma inav in other species be developed before the* pollen. In all these cases cross-fertilisa-tion is alone possible. This may take place in two ways; either tie wind mav carry the pollen "from one flower to another, as in the genus Coprosina, and inmany other cases, or animals may convey it dusted on some part of their bodies. In accomplishing this work insects play a very important role. Birds also fertilise a few New Zealand plants, amongst others the purin (Vitex lueens) and the wainatua (Rhabdothamnus Solandri). —New Zealand Forest Trees as The forests are of great commercial importance to tho colony. Some of the timbers are excellent for "housa-building, others as piles for bridges and sleepers on railways, and some are ornamental, and can be us.r'd for furniture and general decorative work. Tho wood of the kauri (Agathis australis l is celebrated the world over; but, alis! it is rapidly being exhausted. There seems, however, every probability, according to Mr H. J. Matthews, that a kauri forest, from which tho large trees have been cut, would in timo reproduce itself. With this opinion the writer, from lii.s own observations, is quite in accord. The kahikatea IPcdocarpus dacrydioides), the rimu (Dacrydiura cupressinum), and the miro (Podocirpus ferruginea) all afford excellent timber for various purposes, the two latter being confused in many timber yards. The matai (Podocarpus spicata) is a fine, wood for resisting weather, and is only excelled by the totara (Podocarpus totarra) and the Westland pine (Pacrydium Colensrn), the I>. Westlandicum of the 'Forest Flora.' Those two last, also, are used largely for railway sleepers. For fencing posts "tito ptiriri, the broadleaf (Griselinia littoralis). and the kowhai are excellent, but tho first and last become scarcer daily.

It should be nuite feasible to raiso the kowhai artificially in any quantity, since it germinates readily from seed, and will grow very well in the "open. The New Zealand honeysuckle (Knightia excelsa, rewarewa.) is ono of the handsomest woods in the world. Unfortunately, great quantities are destroyed through settlement —a matter whichshould be stopped, if possible. —The Kauri and Kahikatea Forests.— As stated at the beginning of this article, New Zealind contains many varieties of forests. Here only some of tho more distinct are mentioned. The kauri forest extends from the north of Auckland provincial district to about latitude 58deg. It is probably the noblest tree community of temperate "regions. The kauri (Agathis australis) is not a close relation of the Old World pines, but is nearer to tho monkey puzzle family (Araucaria). Certain plants nearly always occur in a kauri forest. These are—Beilschmiedia tariri (the tariri), an abundant and beautiful tree ; the spiderwood (Dracophyllum latifolium, nei-nt-i) ; the fire Coprosina u-rborea; immense tussocks of the sedge (Gaunia xanthocarp.i) ; and of tho kauri grass (Astelia trinervia). Alseuosmia macrophrylla, a plant of the honoysurk'e family, Senecio kirkii, the trec-ferr-—Picksonia lanata, the climbing fern —Lygodium scandens, and the tiny and most graceful tree-'ern—Lom<>ria Frazeri, are also common. Lianes are almost absent on the kauri trees, these giants, standing in close array, disdn'ning all other garb than their own shining armor of bark. Tlie kah : kat"a forest consists almost exclusively of Podocarpus dacrydioides—multitudes of long, straight trunks, like masts of slpps. rising from the swampy frround. High up to-rc climbs the New Zealard screw-pine, the Uiekie, Freycinetia Banksii. which also everywhere forms a rigid entanglement along the fcrest floor. Dead trees bridge the ever-present poo's of water, and certain shrubs form more or less dense thickets. —Variation and Pistrfbution of the Mixed Forost.— The mixed forest varies according to latitude and altitude, but a genera! groundwork of plants is always present, while many Northern forms are wanting in the South. Latitude 58deg forms a fairly dt finite boundary for quite a number of trees and shrubs, and latitude 42deg a second boundary, though this is overstepped in several instances. The pines, as they are popularly called, species of Podocarpus and jJacr>dium, but more correctly designated taxads, since they are related to the yew (Taxus), are important members of the society under discussion everywhere. Confined to tho North are: —Beilschmiedia tariri, the mangaeo (Litsea colicaris), the makamaka (Ackama rosaefolia), the tawibero (Weinmannia sylvicola), the toatoa (Pbylloclnuds glauca), and somo other trees and shrubs. Amongst the trees not spreading much beyond latitude 42deg are eotae very common ones of tho Northern forests. Some , o£ these ar« -.—The karuka (Cprynocarpus laevigata), which reaches Banks Peninsula, J the tawa (Beilschmiedia taw a), the kohe kohe, or New Zealand cedar (Dvsixylum I spectabiie), the rewarowa (Knightia exotica), the pukatea (Laurelia novae-ielandue, the tanekalta (Phylloclauds trichomanoides), and some of the New Zealand olives. The Southern mixed taxad forest extending from latitude 42deg to the south of Stewurt Island is distinguished rather by the absence of the Northern plants than by any peculiar species of its own, though such are cot lacking. The Town Belt of Jrunedin consists of a remnant of such forest, and small pieces exist still all over the east of tire South Island. But ,in the west and south mighty forests still occupy the jjouad. whidi for luxuriance of jsrosalu,

' wealth of ferns, lianos, mosses and Kveri worts can hardly bo surpassed. Here, too, many plants found onlv4n the North Island in the sub-alpine region occur at sea-level. —The Beech Forests.— Tho beech forests, consisting of species of Nothofagus, are quite distinct from all those of which we hare hitherto treated, although they baye some species in common. The dense growth of the foliage abuts out a large percentage of light, and in consequence the undergrowth is scanty. fJome sub-alp ; ne forests of pure mountain beech (N. cliffortioides) contain in many parts little but seedling beech trees. Woody lianes, too, are wanting, and more highly organised perching plants. Nor are turns nearly so plentiful as in the mixed taxad forest. Tho tree-trunks are frequently covered completely with a black fungus (Euantermaria), an account of which extraordinary plant will be,, given when dealing with classification in article 9. Pajai'itic on the beech trees are two mistletoes, the one Loranthus tetrapetalu6, having most showy scarlet flowers, and the other L. rlavidus, with yellow flowers. A small club rnoss, Lyeopodium fastigiatum, is sometime* very abundant on the forest floor. In moist piaces are frequently large colonies of the giunt mots, Polytrichum dendroides, lookim; rather like a pine tree in miniature. Where the forest comes to an abrupt ternr'nation in the sub-alpine region it is invaded by tome of the shrubs ot that zone. At lower altitudes and in the North Island various species of beeches are mixed together, or such a- mixed taxad-Nothcfagus forest may occur as' fringes the West Coast-sounds. No. 4, dealing with New Zealand shrubs rn general, will appear on May 9.