[Read before the Auckland Institute, 31st July, 1871.]
I have delayed the publication of the following notes chiefly from a strong desire to procure alpine specimens of the genus for comparison with the lowland forms, but so far, I regret to say, with but little success. As few genera of New Zealand plants present greater difficulties than Astelia to the student of herbarium specimens only, and on the other hand few are more facile of discrimination when the ripe fruit is available for examination, it seems advisable to place the knowledge already gained on permanent record with a view of facilitating further inquiry.
In the “Flora Novæ Zelandiæ” five species were described, and although numerous dried specimens were forwarded to Dr. Hooker between the publication of that work and the “Handbook of the New Zealand Flora,” an interval of twenty years, no positive additions were made to our knowledge of the genus, notwithstanding that special attention was drawn by the learned editor to the desirability of a revision of the characters laid down.
Although the genus, even with recent additions, contains but seven or eight species, it yet occupies a prominent place in the vegetation of the colony. The geographical distribution of the species is at present imperfectly worked out, but it is known that Astelia Solandri and A. grandis are found from the North Cape to Invercargill. The former, called by the natives “Kaha-kaha,” is abundant, usually growing on the limbs of trees, where it forms masses resembling the nests of immense birds; it is equally common on rocks, especially in woods. The latter, called the “Kakaha,” is not unfrequent in swamps and marshy gullies, and is the largest species of the genus, its leaves being sometimes 8 to 9 feet in length, and 5 inches in breadth.
Another species, A. trinervia, forms a large portion of the forest undergrowth from the extreme north to the Upper Waikato, and probably much further south. A. Banksii is abundant on sheltered sea cliffs, within much the same limits, and the diminutive A. linearis forms large patches on the mountains from the Ruahine southward to Lord Auckland's group and Campbell Island. All the New Zealand species are endemic.
The general diffusion of the epiphytal A. Solandri, and its prominence in all pictures of forest scenery, have doubtless given rise to the erroneous idea that all the large-growing species are epiphytal. In the “Flora, N.Z.,” it is stated that “the large kinds usually form strinking objects on the lofty New Zealand forest trees,” and in the “Handbook” that “the New Zealand species are all diœcious, and from growing on lofty forest trees it is difficult to match the sexes.” Astelia Banksii is specially stated to occur on the limbs of forest trees, but the fact is that only two species are epiphytic, A. Solandri and A. Cunninghamii; the latter rarely or never occurs in large masses so as to form a conspicuous object in the forest. Astelia trinervia, the most abundant of all the species, in the north at least, is invariably terrestrial, as is A. Banκksii. A. grandis is uliginal, and A. Hookeriana rupestral.
All the species are characterized by linear leaves, with broad sheathing bases, more or less silky or shaggy; yet in its habit of growth each species exhibits marked points of difference, which are easily recognized when once pointed out, and in nearly every case the mature fruit alone affords character which cannot be mistaken. The branches of the male panicles are often flexuous and interlaced, especially in A. trinervia, A. Cunninghamii, and A. Banksii; those of the female panicles are rigid and erect, except in A. Solandri. In A. trinervia, A. Hookeriana, and A. Cunninghamii, the elongated scapes are weak and prostrate in fruit; in A. Solandri the scape itself is erect, and the branches pendulous; in A. grandis the stout triquetrous scape, and rigid erect branches, alone suffice to distinguish that species from its congeners, and in A. Banksii the scape, although slender, is invariably erect. The leaves of several species are covered on one or both surfaces with a thin pellicle, which can be detached in long strips.
The flowers of A. Solandri are highly attractive, their bright lemon colour forms a marked contrast with the surrounding foliage, and the plant itself calls vividly to mind descriptions of tropical forest scenery. Some of its immense female panicles contain from 4,000 to 5,000 flowers, and are succeeded by the bright crimson fruit, no less showy. The bright maroon hue of the flowers of A. Cunninghamii is also attractive, but in a much less degree; the handsome erect black purple fruit of A. Banksii is remarkably striking; and the orange coloured berries of A. grandis may be detected at a considerable distance. All the large kinds are sought after when in flower by bees.
A remarkable phenomenon exhibited by this genus is the varying period required by the respective species for maturing the fruit, which may be roughly stated at from five to fifteen months A. Hookeriana occupies the longest period, the flowers of the present season and the immature fruit of the last may be plucked together about the middle of April. A. Cunninghamii flowers in December, and requires a year to ripen its fruit. A. Banksii flowers in April; fruit ripens the following March. A. trinervia flowers in March and April, and ripens its fruit in January and February. A. Solandri flowers in January and February, and requires only five months to ripen its fruit. A. grandis usually attains its maximum of flowering about the middle of October, and has shed its fruit by the end of February.
The perianth is more or less persistent in all the species, but can only be said to inclose the ripe fruit in A. nervosa and A. grandis—the former is described by Dr. Hooker as “having the ovary sunk in the baccate tube of the perianth.” In A. grandis the perianth is slightly thickened, and surrounds the lower portion of the fruit, becoming reflexed and coloured internally as the berries fall. In all the other species, except perhaps A. linearis, the perianth becomes chaffy as the fruit ripens; it is least persistent in A. Hookeriana. All the lowland forms produce staminodia.
The placentation varies in different species; in A. Cunninghamii, A. Hookeriana, and A. linearis, the berry is one-celled, with parietal placentæ, but in the second of these the placentæ are as a rule rudimentary; the seeds are terete, and attached to the placentæ by short funiculi. In the remaining species the berry is three, or rarely five-celled, with black, shining, angled seeds usually suspended from the upper central angle of the cell. The fruit of all the species contains more or less mucilage.
The remarkable similarity in the structure of the seed to that of Juncus has led Lindley and other systematists to refer the genus to Junceæ; but this resemblance is confined to the internal structure; in the thick, hard, and black testa it differs from all members of that order, and still further in the diœcious flowers, the perianth united above the base, the terete filaments, short anthers, the minutely granulated pollen, and the short three-lobed stigma.
At present the members of this genus have scarcely been applied to economic purposes in the colony. I have been informed that some years ago considerable quantities of the shaggy leaf-bases of A. Solandri, the “tree-flax” of the settlers, were collected in the Kaipara, and purchased by an agent, who shipped them to Melbourne, but no one seems to know the object for which they were collected. The leaves of A. trinervia are extensively used for thatching, and the delicate pellicle with which they are invested has been worked into a charming trimming for ladies' bonnets; the same remark
applies to A. Solandri. This pellicle, I am informed, was also used in the early days of the colony for the wicks of bush-manufactured candles. The shaggy leaf-bases of A. Banksii, and other species, are said to have been made into mantles by the Maoris, but I have not had the good fortune to see one*; in softness their silky covering rivals the finest swan down. The fruit of A. Banksii is eaten apparently by birds, but by what kinds is unknown. I have seen hundreds of plants stripped of their fruit within a day or two of its becoming ripe, without a trace being left on the ground; possibly rats may be concerned in the theft. The fruit of A. Solandri makes a clear, pleasant jelly. When the leaves of A. trinervia are cut down a large quantity of a dark jelly-like gum is exuded, but I am not aware that it has been applied to any useful purpose; if of economic value, it may be procured in large quantities at certain periods of the year, as it is often so plentiful along surveyors' newly-cut lines, in districts where the plant abounds, as to prove an inconvenience in walking.
There can be no doubt that A. trinervia, A. Solandri, and A. Banksii, afford a material superior to Phormium for the manufacture of paper, and that it could be supplied in almost unlimited quantities.
Perhaps I may be pardoned for adding that in an account of Cook's New Zealand explorations, published in the colony, the author has strangely identified A. Banksii, or A. Cunninghamii (I forget which), with the “scurvy-grass,” (Lepidium oleraceum, Forst.) of that distinguished voyager. Phormium tenax would be far more easily masticated.
At a future period I hope to prepare a monograph of the New Zealand species. The uncertainty existing as regards the original specimens of Banks and Solander, and the almost total absence of alpine and subalpine specimens for comparison with the lowland forms, renders this impossible at present. The following descriptions, therefore, relate only to forms not included in the “Handbook of the New Zealand Flora.”
[Footnote] * [The following may be useful for reference:—“Leaves and Down from the Kaha-kaka (Astelia, sp.), exhibited by T. B. Gillies, Esq.—A North Island plant that grows in poor clay soil. This down makes excellent pillows, quite equal to feathers, and will probably form a useful paper material. The bulbous part of this plant, as exhibited, yields 10 per cent. of this down.” —“Cat. N.Z. Exhib., 1865, p. 73.]—Ed..