THE SUNDEW
One of the most blood-thirsty of the plant ogres is the little Sundew. We may find it growing on the dark, damp soil of the moors and marshes, by the side of many a trickling stream, or on almost any small patch of boggy ground.
The sundew does not look at all as if it were a dangerous, fly-catching ogre. Nothing indeed, could appear much more harmless than this modest-looking little plant, which consists of half a dozen or so of tiny deep red leaves arranged in a rosette low upon the ground. In the early summer from the center of this leafy rosette a slender flower stalk rises, bearing a cluster of wee, whitish flowers. But about these flowers there is nothing particularly attractive; it is the tiny red leaves of the little plant which claim our interest.
The round-leaved sundew and the long leaved sundew are both common plants in Great Britain; the first has leaves almost exactly like salt-spoons in shape, with little round blades on long, narrow stalks, while the second has longer, narrower blades which remind one more of mustard spoons.
The upper side of each leaf is covered with quantities of red hairs, each one ending in a little rounded knob. These hairs are called "tentacles," and they stand stiffly out from the leaf like a lot of pins stuck in a flat, round pin-cushion. The tentacles are not all the same length. Those on the edge of the leaf are the longest and point outwards, while those in the center are the shortest and stand up perpendicularly, and between the outer and inner rows the hairs are of different sizes, leading gradually from one to another.
The little sundew plant looks very pretty in the sunlight, as every leaf appears to be covered with hundreds of glittering dew drops; but the sparkling drops are not dew; they consist of a clear, sticky fluid which oozes from the round knob at the tip of each hair poured forth from a number of little water pipes with which it is well supplied.
The sparkling drops look very inviting to the flies and midges that swarm in numbers over the marshy ground where the sundew grows. They are much like honey-drops, and few insects can resist the temptation of stopping to refresh themselves when they see such a feast spread out before them. But when a wee fly alights upon one of these sparkling leaves, it finds to its cost that it has been cruelly trapped. Its delicate wings and feet become entangled in the sticky hairs, and the frightened insect struggles to escape.
And now a wonderful thing happens. The hairs which the insect touches in its struggles to free itself pour a regular stream of sticky stuff, from the glands in their heads, on to the poor little creature, and at the same time begin to bend over it. Then, one after another, all the hairs on the leaf, even although they have not been touched by the fly, behave in the same way, curling over like so many clutching fingers to hold the fly down in the middle of the leaf, which at last becomes completely doubled up like a closed fist.
This does not happen quickly. The sundew never hurries itself. One would almost imagine from its slow, deliberate movements that the little plant knew quite well that its prey could not escape. It takes a leaf from one to three hours to close entirely; but long before this its victim is dead, suffocated by the thick sticky fluid with which it is plastered all over. For an insect, as I dare say you know, does not breathe through its mouth, but through breathing pores down each side of its body, and these soon become choked with the deadly stuff.
When the leaf has closed the sundew proceeds to enjoy its meal. The insect is slowly dissolved and digested by the fluid poured upon it by the glands in the knobbed hairs, until nothing but the empty skin remains. Thus the leaf of the sundew is first a trap to catch the insect and secondly a stomach to digest it.
In a day or two, according to the size of the captured insect, the sundew has finished its meal; and the leaf then gradually opens again, disclosing the empty skin of its victim --sucked as dry as if it had been caught and devoured by a spider. The skin soon dries in the sun and is blown away by the wind, and the sundew leaf is then ready for another meal.
It is not only tiny flies and midges that are caught by the little sundew. Quite big flies, blue-bottles, ants, small beetles and butterflies are captured by its hairy leaves. Even a great dragon-fly will sometimes fall a victim to this hungry plant; but when this happens several leaves combine to catch and kill the insect, and afterwards divide the prize among them.
The sundew indeed appears ready for all emergencies, for if two small insects alight on a leaf at the same time, half the tentacles upon it will clutch one insect while the rest turn their attention to the other one. It seems to know quite well, too, when anything falls on one of its leaves, whether it is good to eat or not. Pattering rain-drops, or grains of sand blown on to them by the wind, do not make the tentacles bend; if tiny pellets of paper, little bits of glass, coal or other indigestible things of that sort are dropped upon the leaves, the sundew will have northing to do with them; or if a few tentacles do bend a little to see what it is that has fallen on them, they soon find out their mistake and stand upright again. But if you place a tiny fragment of raw meat or a little piece of white of egg on a leaf, it will close over it, and dissolve it just as it would a live insect.
Sundew plants will live quite well if taken up carefully from their messy bed and placed in a dish, or a saucer, with a little witter at the bottom of it, for they are but loosely rooted in the soil ; and if we are careful to keep them moist and feed them regularly with tiny shreds of meat, they will grow and flourish.
But if you keep a sundew plant, do not make the mistake of giving it large pieces of meat, for plants, like human folk, are sure to be ill if they eat too much. If, in mistaken kindness, you put too big a meal on a sundew leaf, the leaf will do its best to eat it, for unfortunately it does not know when it has had as much as is good for it; and in all probability, like King Henry the First, who (we are told) killed himself by eating too many lampreys, the greedy leaf will die of indigestion.