Symbiosis

1. Biology A close, prolonged association between two or more different organisms of different species that may, but does not necessarily, benefit each member. 2. A relationship of mutual benefit or dependence.

The reason why I thought of writing about lichens and mosses this afternoon is strange. Last week, Shimla saw incessant rain. It rained so hard and for so long that a lot of trees were uprooted, a lot of embankments turned into slush and bore away with themselves many human lives and man-made structures. How strange is man's relationship with nature. On the one hand, man is dependent on it for a host of benefits; on the other, he has today become a parasite - an organism whose existence is injurious to the health of its host.

Moss and lichen are good examples of happy co-existence, of an independent and mutually beneficial relationship. We need to learn something from them.

LICHEN:

Lichens are unusual creatures. A lichen is not a single organism the way most other living things are, but rather it is a combination of two organisms which live together intimately, composed of fungus and alga.

I have seen them grow in all sorts of places: on rocks, fences, trees. Lichens require no food source other than light, air, and minerals. They depend heavily on rainwater for their minerals and are sensitive to rain-borne pollutants. The fungus I am told, produces a sort of acid which assists the process of weathering the rock on the lichen grow, eventually turning the rock into soil.

Before the discovery of aniline dyes, lichens were much used for silk and wool dyes. The blue and purple dyes litmus and archil are still obtained from species of lichens. Others have been used in perfume manufacturing and brewing. The “manna” of the Bible is thought by some to have been a lichen found in Old World deserts and easily carried along by wind.

The true identity of lichens as symbiotic associations of two different organisms was first proposed by Beatrix Potter, who is best remembered for her children's books about Peter Rabbit. In addition to her books, she spent time studying and drawing lichens. Her illustrations are still appreciated for their detailed and accurate portrayal of the delicate beauty of these bizarre organisms.

MOSS:

I've always liked the deep green colour and the rich velvety feel of moss. These are small plants that grow between 0.4 to 4 inches in height. You will observe them growing close together in clumps or mats in shady locations. They love dampness and low light and in Shimla can be found in woody areas and growing on rocks alongside streams. I have observed aquatic varieties along the coast of southern Maharashtra, where moss clings to rocks under sea. One man's weed is another's decoration applies well to moss, especially in Japanese gardening where moss is thought to add a sense of calm, age, and stillness to a garden scene.
People who scoff moss are requested to have a look at this article From the New York Times.