WHEN PLANTS WAGE WAR

Golden Bay Argus, Volume XIII, Issue 1, 2 June 1910, Page 2

WHEN PLANTS WAGE WAR

Little Battles in Byways

and Hedges

The keen competition in commercial circles, even in these strenuous days, is as nothing beside that of many plants and trees for bare existence. Their entire Jives, from the time they form in the parent seed-pod, are beset with peril, for Nature is as much mistress of desi ruction as of creation.

Every plant grov/ing in a wild state has something to combat aga'nst. It may be the war waged against, it by plants of other species, or it may be the likelihood of lo ng devoured by animal or insect.

At the same time, all plants in their wild state are provided with weapons of defence, and often the weakest plant has proportionately the strongest weapon ; directly cultivation is brought about, however, so do the defensive faculties disappear.

This is particularly evident in the case of the garden rdum,_ which, in its natural state, carries long, sharp thorns, as a protection against the browsing animals.

Thorns, spikes, spines, and stiff, bristly growths are the most common forms of plant defence. There are many plants that have spines

only when young, shedding these weapons of defence when old enough and sutliciently strong to exist without them. Other plants, again, carry their spikes, or spines, on the under part of the leaves, to ward off creeping foes, such as slugs. MONKEY TRICKS. In a childish way, we have all looked at the araucaria, or monkeypuzzle tree, and firmly decided that the spikes were indeed to ward off simian acrobats. As a matter of fact, however, the spikes were there for a very different purpose. The trunk of the araucaria is composed of soft, pithy wood, and the sap travels upwards so near the bark that, were this covering broken by a blow, the tree would "‘bleed.” The spikes, therefore, are to prevent a possible blow from reaching the bark ; and as the tree grows, and the trunk towards the base toughens, so do these basal spikes drop off.

The most terrible plant defence of all is that of the wreath of thorns, a creeper that flourishes in the dense jungles of South America. A horse or man struggling through such a jungle, if so unfortunate as to come in contact with this creeper, will rapidly be enfolded with the sinuous lengths, that, snake-like, form a chevaux de frise around the intruder, from the clutches of which it is impossible to get free without assistance. The more the victim struggles, the tighter lie is held ; and this plant can best be described as a series of springs, the tightening of one coil affecting all the others. But often the more subtle methods of defence prove of greater interest than the apparent ones. It is a well-known fact that the animals dislike, drinking water that has lain in the large, bowl like leaves of certain plants, such as rhubarb and the vegetable marrow, and this is merely an unlooked-for scheme of defence.

Other plants, again, ensure their immunity from attack by the indigestibility of their leaves. The rhododendron, for example, has stringy, tough leaves, that must be the reverse of palatable, even to the most goat-like animal. The more familiar laurel is also distinctly uninviting as a dish ; and if a moth were placed in an airtight box with some crushed laurel-leaves, the poisonous fumes would kill the insect.

The problem of poison is not a hard one to solve, and enters very largely into the plan of plant defence. It is obviously harmful for the bark to be bitten from trees, hence on many varieties grows a mos 3 fatal to browsing animals. Yet another form of plant defence is that of odour. In the majority of cases, warning of poison is given to animals by odour. —“Answers.”