THE STALWART LILY

Hokitika Guardian, 26 October 1929, Page 2

THE STALWART LILY

(My Margaret Crookes, M.A.,) In Plant Life of Maoriland. Long ago, the Maoris tell us, before man had been created upon the earth, Tane, the Great God of' the Forest, went through the land seeking a love who should yield him an offspring worthy of a god. But he sought long before he found, .his, desire, and, in his wanderings,, lie met and. loved .Pakoiti, and his spirit breathed upon her. but, alas, from her ; cpmje .no god-like son, but only the Hara-keke, the, flax plants, the stalwart dwellers of the swamp lands and the stiff sentinels of the river banks. In the summer. Hara-kjekej geiids up a rigid, stalk hearing oq , each side of' it dull red flowers, which are even yet “sweet with the honey of . a god’s vain love.” These somewhat dingy red flowers, if not beautiful, are at least extremely picturesque, particularly when they are being fertilised by their sweetvoiced visitor, the tui. It is indeed a charming sight to see him perched upon the tall stem, poking his. parsonical head knowingly Into the depths of the rich .tubular flowers to extract his honeyed meal, while at the same time he obligingly fertilises them, thus enabling them to carry on their all-im-portant work of seed-making. But it. is not flower of the flarakoke that presents points of great interest to the student ,of Nature, butrather its roots and more particularly its leaves. Before considering them

in detail we must bear in min'd itlte' surroundings of Hara-keke, or .Pljibjv mium tenax,' to give it its scientific name. It generally grows in or abijpt samps or upon the,'banks of rivers, and it is in the latter.situation that it reaches its maximum development. There its roots are within reach of a plentiful water supply which has the merit of being both fresh and clean. In a swamp it is not: usually so happy. Truly, it 1 is surrounded' by an abundance of 'water, hut ; it is a case p|f “Water, water, everywhere, hut drop to drink ; r) Swamp' water is stagnant and generally f ull : .of .chemio] matters injurious to the :plant, so tKar-t when it seeks forywater * if; gets as far as in the immediate viqjnifcy ■ T<\ do it sends its Toots ytra^ellirig; long tances a . little below/i tiip- surface bsp that they can satisfy; .•their requirements elsewhere. Moreover,. once tained, if carefully conserves, its wafipj supply by developing a thick opter ering on its leaves so.jt shall' not. IpsP too much through evaporation. Tfie shortage of oxygen occurring in swdflipy soils it obviates by outer parts *of its air storage. _ . ..; r

But it is the leaves of Phormium tliSt Jx a# b^n‘of greatest interest' to both Pakeha and Maori, for the flax industry is the oldest in, New Zealand—unless we except that Interesting .minor trade . in preserved human Beads. 1 . . ' NATURE, TjSE'ENGINEER. ' Apart ftom its great commercial importance, the .flfix ledf ia well worthy of our interest,’ for it is one of the most powerful tension resisting' leaves in the world The' first thing we notice about it’ ! isj' of course, its extreme rigidity: 'lliis rigidity it owes partly to the manner of its growth. When they first leave the. ground, the two blades df the flax leaf are folded/together; indeed, for some, distance they actually grow together; .then/farther up they gradually unfold: It is,, onjy about two-thirds of, the way.,up that the flax, leaf opens out completely. But although this method of. growth is in. itself am excellent defence against that invisible enemy, the wind, it is only when we consider the leafs internal. structure that we understand the cause of , its extreme strength and rigidity. Now in providing its- leaf with a means of strengthening, our flax acts upon exactly the, same principles as do our engineers, in strengthening the bridges the buildings they, design. The only difference is,, that the strengthening appliances of plants are infinitely more perfect and economical than anything so far invented by the brain of man. Now for strengthening purposes an engineer will very often use irop girders. A simpe girder consists of two parallel, pieces ot iron joined together by a cross-piece. In Cross section it resembles an “I”. The cross piece of an “i” girder (known as the web) need not necessarily be as strong as. the parts it connects, as it is not exposed to so much strain. In iron bridges, for instance, we often find that the webs of girders consists of lattice work. Of course the advantages of the girder, consist of lattice work. Of course the advantage of the girder is that it gives the maximum amount of strength with the maximum amount of material. STRONG AS STEEL.

Bearing these things in mind, let us return to the strengthening sySr tern of our flax leaf. The flax leaf is as a matter of fact fortified along its entire length by vegetable girders. If we were to examine a cross section of the blade of the leaf under the microscope We should find it is traversed longitudinally at 'right angles to its surface by bands to tissue that have all essential qualities of girders. These “girders” consist of two parallel hands of very strong fibrous tissue jpmed by a “web” of rather more delicate 1 tissue consisting of the. minute, tubes that carry nourishment from stem to leaf and vice versa. This more delicate tissue constitutes an excellent web for the girder, while at the same time its own fragile parts are protected from undue strain, by the stout fibres.

Alternating with the larger “girders” there are smaller bands of fibres situated just below the under surface of the leaf'. These help to protect the under surface from the danger of undue compression. Perhaps some readers may thixlk it an exaggeration to compare these vegetable fibres to the huge . girders of our big: buildings and bridges. But as a matter of fact a celebrated German botanist,: Scgwendener, who carried out a lofigi serious of researches on the strengthening tissues of various plants, has calculated that the fibres of Phor r mium tenax are equal in sustaining power to the very best wrought iron or hammered steel, while their ductility is ten id fifteen times greater than that of iron. The same botanist has also recorded that the absolute strength of such fibres increases according as the water' they contain, diminishes. Consequently we are not surprised to learn that the. hard, dry, thick-Valled cells composing the fibres of Phormium are filled only with air. Small wonder, then,' that the flax leaf has yielded to our industrialists such wonderful and valuable fibres'. J •

I have already given as reason for the toughness' and strength of the PhormiUm, leaf, the fact that it must protect 1 itself, against the wind and loss ef water'through evaporation. But Hon G. M. Thomson jiaS'made, n third suggestion which is distinctly Tfiscinafcing. He thinks that the finx leaf may have originally developed its great partly as a protection .against moas. weaker'leaved speciments having been trampled down in the course of ages. This is a most intriguing idea, caling to mind as it does a picture of huge powerful legged birds stalking over the country’, making their way among flax clumps dwarfed to the size of large tufts of grass in comparison with their enormous stature. But however, that may be, the Phormium leaf remains remarkable for its great strength; And ir their strange member of the lily family (for it is a true lily) cannot vie with its Home relatives for grace and beautj, nevertheless our Harn-keke may claim pre-eminence for strength and use'