THE NATURALIST.

Otago Witness, Issue 2520, 2 July 1902, Page 76

THE NATURALIST.

How Plants Manage to Prolong 1 ife-

A single leaf of an apple tree has 100,000 pores, and through every one of these water v constantly passing off into the surrounding atmosphere. Air lias an enormous appetite for water, and the drier it is the mon it takes up. Thi.s is easily proved by hanging out a wet cloth, and seeing how yoon it becomes dry'

Considering the way in which the atmosphere is constantly forcing the apple tree and every other plant to give up ]ts moisture, the marvel is that, after a very fewdays of hoi sunshine, every plant does not wither and dry up. Yet even those growing in light soil and exposed situations manage to withstand weeks of drought without losing their greenness. More marvellous still, acacias and cacti will grow und remain green out on the wastes of fiery deserts in North Africa and in Arizona. ■

Plants, like all other living things, have learned to adapt themselves to their situations, and to take precautions accordingly. Water to plants is more valuable than gold is to us human beings, and where the supply is scanty they have learnt to hoard it as carefully as a miser does his treasure. Plants cannot refuse to give up water altogether, for otherwise they could not grow. All their food is: taken up by their roots, dissolved in water. This sap rises through their veins and feeds them. They makp use of the mineral matter, and then let the water which contained it escape through their lungs — that is, their leaves. But their methods of holding on to sufficient water to keep them green and nourishing are many and ingenious. Go out and pick a leaf from any plant or shrub — a hawthorn leaf, for instance. You will notice that its upper side is much smoother than the under.

The under side looks dull in comparison. This, is because the upper side is exposed to the direct ray? of the sun. The glaze prevents the hot "rays sucking all the w ater out of the surface of the leaf. Some plants, indeed, refill entirely to part with water through the upper side of the leaf. Laurustinus and lilac-leaves have no pores at all on the shiny upper surface of the leaver.

Pine-trees inhabit dry, sandy soils. These refuse to grow wide leaves, but confine themselves, to producing thick, fleshy upedles, which have very few openings through which the water can escape. C'ab-t-ages need an enormous quantity of water; but unless the supply was absolutely unlimited, their big leaves would give up so much to the air that, without vome means of checking this ovcr-libarality, they would v ilt and die.

Cut a fresh cabbage leaf and examine it. It has a sort of dusty, mealy look. Put the leaf under a microscope, and you will ste that this "bloom" is composed of tiny needles of wax. The cabbage has produced the wax to protect itself from the water-stealing rays of the sun. Australia is the drie'-t of all the contirents; yet it ha* plenty of trees. They nfver grow any more leaves than they absolutely need, and they take the additional piecautiou of turning these leaves edgeways, so that those water-thieves, the sun-rays, cannot fall direct upon their broad surfaces.

Au.strahan acacias go a step further still. When they are fully grown they shed thenleave? altogether; they keep the leafstalks, and produce two tiny wings, whica present their edges to the sun. In spite of all the.-c various precautions, the amount of water which growing plants part with to the air i> almost beyond beliei. A squate foot- of long pasture grass gives off neaily 4 2-sth pints of water every 24 hours in dry wea'her. That is to say, there lises into the air 106 tons of water from each acre of meadow within one summer day and night. One single cabbage has been measured to give off two pints .md a-half of water within «i similai period As for the amount big trees uive oft", it is ei.onnoti-. A 60tr. elm will have about 7,000 000 leaves. If bpread out, these would co\ er 200,000 square feet, or five acn-s. From these leaves there piss out into the air within a summer dayover seven tuns of water in ihe form of vapour.

Do Birdb Feel CVidY — Sometimes one is iiliu<3>t dnveu J* duulrt, whether bixda cab

feel cold at all. The other morning I saw to starling, a sparrow, and a greenfinch, all fcathing at the same time in a frozen cart rut, -where the ice had been broken by a passing wheel. The same afternoon a number of starlings were bathing, just before going to roost, at a place where the ice was broken on the pond, and when we had to use a cart horse to break the ice another morning a crowd of sparrows came Shopping behind his heels, eagerly jo&lling one another to bathe in the ice-cold water. Ducks, again, sleep comfortably with their bare feet on the ice all night. From the joy with which they flock to an ice-cold bath in winter, it is evident that the feeling of cold cannot be painful to them as it is to us. — Country Life. An Ivory Coast Monster.— When the Hostains-D'OUone expedition we're cutting then- way through the vast forests of the Ivory Coast they came across the skin of an unknown animal in a native hut. "This fikin was of a greyish brown," writes Captain D'Ollone, in his recently published account of the journey, "with short bristles 3ike those of a large shaving-brush ; unfortunately, the head and the paws were missing. The people gave us the most extraordinary* details about the ble (as they called this strange animal). I will repeat them, because precisely the same details have been furnished to us in various localities, and it will be seen how difficult it is to sift the truth in native stories: — "The ble is extremely brave and strong. It attacks and Mis all the animals it encounters, even the panther, the elephant ( !), and man. This is its method of fighting: when it is close to its adversary it squirts at him a jet of corrosive liquid, which blinds him or causes him the most intolerable itching ; then it gets up on its hind leg:-, and with its front paws, which are like hands, and conlain a kind of hard excrescence, falls upon him and claws him.' But here is the best thing of all: — 'It is not ot all carnivorous f.r\Cß its enemy is killed it strips him of Ms skin, in which it arrays itself, and £*pcs off disguised in this manner ; only as the skin covers its head it is no longer able to see, and thus it happens that several have been killed even by women!' Making due allowance for imagination, several characteristics are to be noted here which recall the pole-cat (jet of liquid), the bear «md the kangaroo (fighting in an upright position with the forefeet). Perhaps naturaiists will find in it a new subject for investigation. . . ."