New Zealand Plants and their Story
Chapter XII. — The Classification Of The Plants
The Classification Of The Plants.
Popular plant-names and their defects—Advantage and meaning of scientific names—Explanation of terms "genus" and "species"—Principal divisions of the plant kingdom—Rapid glance at the families and genera of New Zealand flowering plants—Ferns, mosses, fungi, and algae—The slime fungi partly animal, partly plant.
Certain New Zealand plants possess two kinds of names—popular and scientific. The former are either English or Maori. The English names are for the most part those which have been given by the early settlers, partly from some likeness, real or fancied, to the plants of their native land, and partly from some peculiar characteristic of the species in question. To this latter category belong such names as lacebark, ribbonwood, spiderwood, milk-tree, pincushion-plant; and to the former, birch, ash, honeysuckle. Some names have been bestowed for jocular reasons—e.g., lawyer, wild-irishman, spaniard, and nigger-head. Finally, a few are the work of botanists who have sought, vainly for the most part, to bring into use a nomenclature that should have a more correct English equivalent for the scientific name—e.g., speedwell for Veronica, groundsel for Senecio, palm-lily instead of cabbage-tree, beech instead of birch, &c. Some English names are corruptions of Maori ones, as biddy-biddy for piripiri, cracker for karaka, maple for mapou. This origin of names is quite an interesting study in recent word-making, and is well worth investigating.
The Maoris, living as they did in constant touch with nature, possessed much more knowledge of the vegetable products of New Zealand than do most of their more enlightened, but in some respects degenerate, white brethren. For all the more common trees and shrubs the Maoris have names. But both Maori and English names are used loosely, some being applied to more than one species, or having a different signification in different districts. Akeake is applied to Dodonea viscosa, Olearia Traversii and O. avicenniaefolia; koromiko page 154is the name for several species of Veronica; toetoe is the name for a large number of grasslike plants, and totara for the lofty taxad equally with the dwarf heath Styphelia Fraseri. Other instances could be given, but these will suffice. Further, many plants have neither a Maori nor an English name. From the above it may be seen that the popular names are of no use when we wish to make an accurate list of even the seed-plants of any locality, and that names having a definite application must be used. For this reason the scientific names have been designed.
Scientific Names of Plants.
The scientific names are in Latin. The use of Latin among learned men dates, of course, from the time of the Romans; but its application to plants, as we now know them, began in the sixteenth century, when modern botany was born. Latin was then the universal written language of the learned, and the early botanical works were all written in that tongue. This usage of Latin has proved very convenient in practice, for it would lead to endless confusion did the plants bear the popular names of their respective countries alone. As it is, a definite scientific name is applied to one particular species, and to that only, and such names are recognised by scientists, no matter what their nationality.
Each scientific name consists of two words, the first denoting what the genus is, and the second the species to which the plant belongs.
Meaning of Terms "Species" and "Genus."
To write down the word "species" is much easier than to define what a species really is. In fact, when it comes to fixing the limits of a species, scarcely two classifiers can agree. Elementary species, as defined by De Vries (see Chapter I), are the units of the plant kingdom. Such are those groups of plants which differ from all others in certain distinct characteristics, and reproduce themselves "true" from seed. But this experimental method of separating species is not yet in vogue, nor does it seem altogether practicable.
The species, then, of the classifiers are founded by the comparative study of large numbers of individuals, and if a group of such has some distinguishing characteristics which separate it from all other groups of individuals, it is classed as a species. Such a group of individuals may form a true species, which will reproduce its kind, page 155or it may be made up of a number of elementary species. Thus the species of the botanist are by no means equal in value. In practice, however, if a number of plants resemble one another almost exactly, they may at once be concluded as belonging to the same species.
If a number of species agree in certain particulars so that we may conclude they have descended from some common ancestor, they are said to belong to the same genus, and we have the next wider group of plants. Suppose we find a number of plants which, although they differ much in stature, shape of leaves, habit of growth, size and colour of flowers, and in other particulars, yet have all four petals, eight stamens, the calyx-tube attached to the ovary, and produce after flowering a narrow, elongated, 4-angled capsule, which splits open from the apex downwards into four sections, revealing a large number of seeds, each provided with a tuft of hairs at the apex, then all those plants will belong to the genus Epilobium (fig. 63). These plants, again, will vary much amongst themselves; but groups having distinguishing marks for each group can be found, and such groups will each represent a species. There are in New Zealand between thirty and forty species of Epilobium, which are distinguished from one another by distinctive marks, and each bears a name—e.g., Epilobium glabellum, E. Hectori, E. pubens, &c.
Originally the second name had a meaning which was supposed to be appropriate to the plant, but the number of specific names has so increased during the past hundred years that it is no longer possible always to find an appropriate appellation. So modern botany has decreed that a specific name once given must stand for ever, even where the name is quite inappropriate. This means that a name is now considered merely as a name and nothing more, and need have no meaning whatsoever.
Another matter which must be remembered is that generic differences generally depend on the structure of the flowers, and not on the leaves. That a plant has leaves like a willow does not constitute it a willow; similar plant-form, as has been already shown in this book, occurs amongst plants quite unrelated. Leaves, however, amongst other characters, are made use of as marks of specific differences.
Fig. 63.—Epilobium chloraefolium.
[Photo, L. Cockayne.
Classification goes still further. A number of related genera make a family, and so on, until such fundamental divisions of the plant page 157kingdom are reached as—slime-fungi, algae, fungi, liverworts, mosses, ferns, conifers, seed-plants with one seed-leaf in the seedling, and seed-plants with two seed-leaves in the seedling.
The families are now most frequently arranged according to the manner in which they are supposed by some to have originated, the more simple coming first and the more complex last. Thus, amongst seed-plants the pine-tree family begins the list, and the daisy family completes it.
Considering the seed-plants alone, New Zealand has between fourteen and fifteen hundred species, about three-fourths of which are found nowhere else, the number varying according to the computer's conception of a species. Cheeseman gives 1,415 as the number, but the writer's estimate is somewhat higher.
It would be out of place to go at any detail into the families and genera, so only a few of the more interesting are mentioned. Neither can any attempt be made to define the families, &c., in popular language—a task of extreme difficulty, and, when accomplished, harder for the beginner to understand than would be his learning the necessary technical terms, which have a definite meaning and can be used with precision.
The Families and Genera.
The daisy family (Compositae) is the largest of our families. What is popularly called the flower is not so, but is really a collection of small flowers placed closely side by side upon the expanded summit of the flower-stalk, and forming a "head." The cotton-plants, or mountain-daisies (Celmisia), the groundsels (Senecio), the vegetable-sheep and its relatives (Raoulia), the cotulas and the helichrysums belong to this order. Many are amongst the most striking of our plants, both in form and flower.
The bluebell family (Campanulaceae) has not many representatives with us. It contains the New Zealand bluebell (Wahlenbergia saxicola), whose white or bluish flowers are so conspicuous a feature of the upland meadow, and the pretty white pratias which are related to the well-known lobelia of gardens.
The madder family (Rubiaceae) contains the large genus Coprosma, which is closely related to the coffee-plant. Coprosmas can always be recognised by the male and female flowers being on different plants, and by the berry-like fruit containing two plano-convex stones.page 158
C. grandifolia has very large leaves and reddish-orange drupes, and is common in North Island forests, and extends, south as far as Greymouth and Kaikoura. C. Peiriei forms a close turf in the drier South Island mountains, and has large port-wine-coloured drupes, which occasionally are white and translucent. Many co-prosmas are shrubs of a dense habit of growth, with slender inter-lacing branches.
The figwort family (Scrophularinaceae) contains the very large genus Veronica and other genera of showy plants (Ourisia, Mimulus. Euphrasia, &c.).
The convolvulus family (Convolvulaceae) contains the beautiful climbing-convolvulus (Calystegia tuguriorum) and the lovely purple Ipomaea palmata of the shores of northern Auckland.
The borage family (Boraginaceae) comprises the forget-me-nots.
A little lower down the scale come the gentians (Gentianaceae).Owing to the bitter principle in their roots, these plants are not relished by stock. Possibly the root could be used as a tonic, like that of the European Gentiana lutea.
There is only one plant of the primrose family (Primulaceae), Samolus repens, a prostrate, white-flowered plant forming broad patches in salt meadows.
The heath family (Ericaceae and Epacridaceae) is important, as it contains many common shrubby plants. Draeophyllum, with needle-like leaves, and Gaultheria, with lily-of-the-valley-like flowers, are the most important genera.
The carrot family (Umbelliferae) is well represented, and contains one of the most remarkable genera of the flora, Aciphylla.
The willowherb family (Onagraceae) is represented by the large genus Epilobium. The species are not yet well known, and they are difficult for a beginner to determine. Some are distinctly pretty— e.g., E. pallidiflorum, E. macropus, E. vernicosum. Others become terrible weeds in an alpine garden—e.g., E. nummularifolium, E. linnaeoides. The fuchsias belong to this same family. Other related plants, though belonging to a different family, are the myrtles and ratas, both of which include some beautiful species—e.g., Myrtus bullata and Metrosideros lucida (Myrtaceae).
The mallow is a very showy family (Malvaceae), and contains some small-trees most valuable for garden purposes, as the lacebarks and ribbonwoods.page 159
To the Elaeocarpaceae belongs the native currant (Aristotelia racemosa), one of the "fire weeds" of New Zealand—i.e., a plant which comes up abundantly after a forest is burned. Here also comes that fine tree the hinau (Elaeocarpus dentatus) and the pokaka (E. Hookerianus), with its distinct juvenile and adult forms.
The New Zealand geraniums belong to the family Geraniaceae. They are generally rather insignificant, though their first cousins the pelargoniums of gardens, incorrectly termed geraniums, are amongst the most showy of plants.
To the pea family (Leguminosae) belong the New Zealand brooms (Carmichaelia) (fig. 64), of which there are nineteen species, all of which have remarkable contrivances against drought. Here also comes the yellow kowhai (Sophora microphylla and its allies), and a rare mountain - plant, Swainsona novae-zelandiae, of Australian affinities. Then there is the parrotbill (Clianthus puniceus), which is related to Sturt's desert-pea of central Australia.
The rose family (Rosaceae) lacks in New Zealand the true roses, but is represented by the genera Rubus (five species or more), to which belongs the bush-lawyer; Geum (six species, all but one mountain-plants); Potentilla (one species); and Acaena, to which belong the species of piripiri—plants very unlike roses.
The pitchy-seed-family (Pittosporaceae) is common in all our forests. The genus can be recognised by the large capsules, which, when they open, contain black seeds imbedded in very sticky matter. P. tenuifolium, so largely used as a hedge plant, is wrongly called matipo by the gardeners, which is the name for various species of Suttonia.
Saxifrages (Saxifragaceae), plants so essentially alpine, are wanting in New Zealand; but we have some forest-trees belonging to the family—e.g., the putaputaweta (Carpodetus serratus). Weinmannia racemosa, called red-birch in Westland, is very common, and belongs to the Cunoniaceae, a most closely related family.
The sundews. (Drosera) belong to the family Droseraceae. There are six New Zealand species in the genus.
The magnificent magnolias of America and Asia (Magnoliaceae) are absent from our forests, their representatives being shrubs with rather insignificant flowers, the pepper-tree (Drimys axillaris, D. colorata, D. Traversii), a relation of the well-known Winter's bark of South America.page 161
New Zealand genus, and L. oleraceum, Cook's scurvy-grass, the most celebrated plant.
To Loranthaceae belong the mistletoes.
The nettle family (Urticaceae) is distinguished by the appropriately named shrubby nettle, Urtica ferox.
The beeches (Fagaceae) have been noted when dealing with the beech forests in Chapter III.
To the pepper family (Piperaceae) belong the kawakawa (Macropiper excelsum) and the succulent herb Peperomia Endlicheri.
Among the seed-plants which have only one seed-leaf in the seedling comes the important family of orchids (Orchidaceae), of which we have between fifty and sixty species, some few of which live upon trees and have aerial roots.
To the iris family (Iridaceae) belong the pretty and easily cultivated libertias.
The lily family contains the palm-lilies (Cordyline, cabbage-tree), and the New Zealand flax, of which there are two species, P. tenax and P. Cookianum, as already noted.
The palm family (Palmae) has two representatives—the nikau (Rhopalostylis sapida), and one found only on the Kermadec Islands, in the New Zealand region, but extending to Norfolk Island, R. Baueri by name.
The rush family (Juncaceae) is an extensive one, consisting of the alpine or subantarctic Rostkovia, the true rushes (Juncus), and the wood-rushes (Luzula).
The sedge family (Cyperaceae) contains many genera, some of which are frequently mistaken for rushes and others for grasses. Rushes, however, have flowers with small but distinct outer leaves; grasses have hollow jointed stems and leaves with split sheaths; and sedges, &c., have solid stems, frequently angular, and the leaf-sheaths not split.
The grasses (Gramineae) are almost the most important natural order, for their economic value cannot be overestimated. Some of the species are of extraordinary size—e.g., Arundo conspicua, Danthonia Cunninghamii, and D. antarctica, this latter belonging to the subantarctic islands. Others are extremely minute, as Agrostis muscosa, which forms small cushions on bare, wet ground in the subalpine and montane regions, and even occurs at sea-level in some places.page 163
The pine-trees, belonging to two families (Pinaceae and Taxaceae), conclude the seed-plants, and differ from all treated of above in that the ovules are naked and not enclosed in a closed chamber (ovary). The most curious of our taxads is Phyllocladus, whose "leaves" are really flattened stems, which in appearance exactly resemble leaves. True leaves, however, are to be seen on seedling plants.
The Lower Plants.
The seed-plants do not by any means comprise the whole of the New Zealand flora. There are, for example, more than a hundred and fifty species of ferns and their allies, including one genus, Loxsoma, peculiar to New Zealand.
Ferns differ greatly in their form and the texture of their leaves. Some possess two different kinds of leaves—namely, those which bear spores and those which do not, the latter having generally a larger area of surface. The genus Blechnum is especially distinguished by its two forms of leaves. Generally the leaf-surface is more or less vertical; but in Gleichenia it is horizontal, whence the species of that genus get the name of "umbrella-ferns" (fig. 66). To the genera Hymenophyllum and Trichomanes belong the beautiful filmy ferns. The leaves of these ferns are generally much divided, but those of the kidney-fern (Trichomanes reniforme) are entire. This fern, notwithstanding its thin leaves,* often grows in remarkably dry stations, as on Rangitoto Island, near Auckland City.
The mosses and liverworts embrace hundreds of species living under all kinds of conditions, and varying in size from the giant Dawsonia superba, 2 ft. or more tall, to tiny species of liverworts (Frulania, &c.) clinging to the bark of trees. Very interesting is the way in which both mosses and liverworts build up great cushions in stations where the air is almost constantly saturated with moisture. In the forests of Stewart Island, but chiefly in the south and west, the cushions look just like moss-covered boulders (fig. 67).†
Fig. 66.—The Umbrella-fern (Gleichenia Cunninghamii).
Lands Department.] [Photo, L. Cockayne.
After the fungi come the algae, salt water and fresh. Macrocystis. a brown seaweed, attains an enormous size, and lengths of many hundreds of feet are not unknown; indeed, this plant may be the famous "sea-serpent."
Then we have the bacteria—the "microbes" of the newspapers—all infinitesimally minute plants; some the greatest of benefactors, and others the deadly enemies of mankind. And finally come the slime-fungi (Myxomycetes), which may be seen as masses of jelly on rotten wood, and which, moreover, are at one period of their existence animals, and at another plants!
* It has thicker leaves than the other filmy ferns.