Читать книгу Birds and Nature, Vol. 10 No. 1 [June 1901] - Various - Страница 7

No doubt every one knows the Lichens, the greenish gray growths, sometimes like rosettes or clusters of leaves or of fruit, on tree trunks or the gray rocks by the water, and even on the ground and old wood. Their forms are various and often graceful, and mingled with their greenish gray are many brighter colors, giving a rich tone to the rough surfaces they cover and adorn. But I dare say that most of us have thought of a Lichen as a single plant. It is not so, though it looks so exactly like one in its close union. It is a partnership, indeed; generally what looks like a single Lichen is a colony of partners keeping house together, or a manufacturing firm, if you like that expression of their business better. The partners are also kindred, or were so, in the past.

For there was a time long ago when there was only one big family of plants, the Algae; the brown Algae or seaweeds known as kelps often form the “wrack” or tangle of weeds like long leaves or branching stems, with berry or fruit-like bladders, thrown on the coast in great masses by a storm; and the red Algae, or the beautiful fern-like and coral-like seaweeds that grow far down in the deep sea. There are also the green Algae, found in fresh water, or even on damp tree trunks and rocks. They have many odd forms. One kind, called a pond scum, is a frothy, slippery mass of spirally wound bands, floating in ponds or still water; another, called “green felt,” is found in water also, and has egg-like things from which spores or seed-like bodies escape to form new plants. They have filaments at the bottom, like roots, that are called “holdfasts.” Lastly, there are blue-green Algae, jelly-like masses found on trees, rocks, damp earth or floating as green slimes in fresh water. Most water plants are active and independent. They are on the upward road, for though they have not distinct stems, roots, leaves or fruit, their different parts, as I have already said, show a decided likeness to these, especially their “holdfasts” to roots and their air-bladders to fruit. The exquisite red seaweeds are as graceful in form and vivid in color as many flowers.

There is a remarkable foreshadowing of the moral law even among these early growths. Some have shirked their work, which was to absorb waste substances, and manufacture these into organized plant food. They tried to live on other growths, to the injury of the latter, and even sank to feeding on dead substances. They lost the green chlorophyll, which is necessary for manufacturing, though the red and brown Algae do not show its presence because their other coloring is more vivid. But it is present all the same with every busy, self-respecting plant. The lazy, pauper growths deteriorated more and more and at last were no longer Algae at all, but Fungi. They could not live by themselves; their only chance was to get active or well-stocked partners. As the Alga developed more and more into a likeness of a perfect plant, so the Fungus grew less like one. The white furry “mould” on bread or preserved fruit, the “mildew” on grapes and lilac leaves, the “black knot” of cherry and plum, the “ergot” of rye, the “rust” of wheat, do not look like plants unless you study them through a magnifying glass. Nor do the “slime moulds” or the mushrooms, toadstools, puff-balls and truffles bear much resemblance to flowers. Some of these, however, are both pretty and useful.

In the case of a Lichen the partners really seem to be of use to each other. The Fungus is not a mere pauper living on his more active kinsman. If you examine a Lichen you will find a large number of transparent threads, and in their meshes lie the green Algae, giving the whole a greenish tint. The little cups or discs of the Fungus that appear on the surface are lined with vivid colors, and have delicate little bags or sacs, with seed-like spores inside. The Fungus supplies a shelter from extreme cold, and also holds water in which the Algae finds raw material. It is like a man and wife housekeeping, the man providing the house and the raw stuff – flour, eggs, sugar, etc. – and the wife makes these materials into food. Plants, by aid of their green stuff, work over the carbon and other materials they get from air and water and make sugar and starch, or organized food. This is their manufacture and they must have an abundance of light to do it well, so when the sea Algae grow to be immense kelps or seaweed, hundreds of feet long, they are kept afloat by their air bladders. Now, it is true the Fungus in our Lichen could not live at all without its busy Algae, which it holds in its transparent filaments, but it is not a useless partner, so we will not call it evil names. I think you will be surprised to hear, after all the warning given by these dependent and generally worthless idlers in the plant world, some of the beautiful and blooming flowers have fallen into their bad habits and are regular underground thieves.

For the Gerardia or false foxglove has established no partnership; it is plain stealing. It still works, so it has not lost its green of the leaf, or the purple and gold of its flower, but it steals the materials for its work. When it becomes utterly idle and useless it will lose all its color and be like the ghostly white Indian pipes that grow in the shadowy pine woods.

It is interesting to know how it steals. In the dark basement chambers underground the root servants of the plant move slowly in a certain circle that corresponds to the circle of light that the branches describe overhead. Within this space they gather chemicals from the soil and store up moisture, sending these by the sap up their elevators to the well-lighted leaves, where the manufacturing of starch and sugar goes busily on. Now, the Gerardia, being too trifling to collect its own stuff, sends suckers into the roots of other plants and greedily absorbs their contents. That is the reason it is so hard to transplant the Gerardia – its roots are enmeshed and entangled so in other roots below ground. A very odd thing sometimes happens to it. In the dark the roots occasionally blunder and tap other roots of the same Gerardia, just as if a pickpocket in the dark were by mistake to put his hand slyly into his own pocket and steal his own purse.

Ella F. Mosby.