OUR NATIVE FLORA.

Auckland Star, Volume LVI, Issue 162, 11 July 1925, Page 35

OUR NATIVE FLORA.

A BOTANIST'S JOTTINGS. THE GIANTS OF FERN-LAND. By MAKGUERITE W. CROOKES, M__k. It has been suggested by competent authorities that the beautifully fashioned spirals that form so characteristic and charming a feature of Maori art were first inspired in the Maori mind by the beautiful curves of an unrolling tree fern frond. Be this as it may, we can be sure that the beauty-loving soul of the ancient Maori delighted wholeheartedly in these lovely and graceful denizens of the New Zealand bush. However, his interest in the different tree ferns was certainly not purely aesthetic. Take, for instance, the mamaku, or "black tree fern" (Cyathea medullaris). This is one of the largest and most handsome of all our v tree ferns. It can be distinguished by the black stalks of the fronds and the leaf scars that form a definite pattern all round the slender black stem. Only when the tree is young do the old ragged fronds hang about the stem; as it grows older they break off, thus giving the plant a particularly graceful and trim appearance. Looking at the strong, slim black stem, which for all its slenderness is nevertheless able to support a great crown of fronds, often 30ft across, one might compare it with many things, but generally the last thing a European would associate with it would be food. But the Maori had an unerring instinct in such matters. Attacking a suitably sized fern, he would split open,the stem and extract from the slimy, pith the "pitau." This would be cut into small slabs, threaded on strings of the everuseful flax, afterwards being baked in the "hangi," or Maori oven. The result was a form of dessert rather resembling dried apples., A Hardy Beauty. To the modern New Zeaiander, how- ■ ever, the mamaku serves, not as an article of food, but as a charming addition to his garden. Fortunately, it grows very well out of the bush, in favourable situations attaining a height of sixty feet. It is extraordinarily hardy, and seems to have great powers of recovering itself after an injury. I have seen specimens that for some reason have fallen over so that the stem, eight or ten feet long, lay horizontally along the ground, gradually bend up the end of the stem so that the crown of fronds should be in the right position as regards light, and proceed to grow a vertical stem from the point of bending. Perhaps this may prepare the reader for a story Mr. Dobie recounts in his "New Zealand Ferns." He tells how an eleven-year-old tree fern in his garden, which had attained a height of ten feet, one night during a heavy gale snapped clean in two near the -ground. - -Mr.; Dobie took the Bevered stem, with its great crown of fronds, and he says: "I dug a hole, placed it in, and rammed it tiffht like, a fencing, post. After struggling through the summer it began to put out ne\y fronds, and now shows signs of a complete recovery!" , The mamaku indeed seems "supremely fitted for cultivation, and it''has.the advantage of beinj? the most quicklygrowing of all our tree ferns, Mr. Dobie has studied it most carefully,., through considerable number of yearsj and' finds ' that it grows about a foot a year. He found that the average daily growth of a-frond was about two inches, while-in some cases a maximum daily growth of four inches was attained. Like all ferns, the mamaku is unable to add to the thickness of its stem hy producing rintrs of secondary wood. But _ when one path is closed to her Nature will take another. Tree ferns are capable of producing larger numbers of , aerial mots that form a thick matting —round the stem. In the mamaku the aerial roots often form powerful buttresses. It is quite common to see on a steep hillside a mamaku that is exposed to a great strain owing to the fact that its stem is not vertical, but bends over. ' pometimes quite considerably to one side. Tn such easps the fern! like a wise engineer, strengthens the stem at its weakest point. It puts down a solid mass of aerial roots from the under side of the '. lower part of the stem, thus forming a powerful and efficient prop. Pointing the Way. Another beautiful tree fern that grows lustily'throughout the dominion is the "Ponga," or "Silver King," known to botanists as Cyathea dealbata. It is. extremely easy to identify, because the, backs of the fronds are always pure white, while,the stems are a warm nutbrown colour. It is not so large as the mamaku, reaching a maximum of twenty feet in height, while its fronds axe never more than twelve feet long. Like the mamaku, it was put to good. use by the old-time Maori.' It is said j. that, long ago, when planning a surprise s raid upon an enemy pa, scouts would \ first go through the woods in the day-> .time seeking the best avenues of attack. The track would then be marked by fronds of the ponga being laid upon them white side uppermost. Then when night came the keen-eyed warriors would have no difficulty in picking up the pathway to the sleeping pa. Still another tree-fern abundant throughout the , colony is tha wheki i (Dicksonia squarrosa.) This fern may be identified by the remains of the stalks of the dead fronds. These are dark brown or black, about nine inches long, and remain standing up against the stem all the way along it. The wheki does not grow more than twenty feet high, and the fronds are from four to eight feet long. Like its relatives described above the wheki was beloved by the Maoris, but for different reasons. It was used neither for food nor for track marking, but for building purposes. ' They often used the stem in the construction of their huts, no doubt choosing it because it lasts well in the ground. For their more important buildings, such as whare-punis, they would carefully trim off the outer part of the stem, so that the beautiful grey and black markings underneath were exposed. The stems were then set at regular intervals to act as columns for the house in question— and very handsome and attractive columns they made. Like its relatives it grows well in cultivation, and next to the mamaku it is the most quickly growing of our New Zealand tree-ferns, the average daily growth of a frond being one and three-garter inches, while its maximum is two and seven-eighth inches. Nature has been bountiful to New 1 Zealand in the matter of tree ferns, and there are other beautiful and interr esting species besides the ones described above. These are but three of the most striking of a group world-famed for