And, used wisely, plant products are an entirely sustainable resource. Fibres, the strengthened vascular tissues extracted from plant stems, are one of the most ancient and valuable of plant products. People use the fibres of over 2,000 plant species, although no more than about 40 are known to be traded at all widely. Linen was well known to the ancient Egyptians and is making a comeback in the modern world as a luxury textile. Hemp has long been used to make clothes and, like linen, is being promoted by the fashion industry, as well as making a good quality paper.
Oil is extracted from the seeds, which are widely sold to feed cage birds.
Bamboos, huge rhizomatous grasses with hollow, compartmented, woody stems, continue to provide one of the major structural materials of tropical regions, especially Asia. The living plants, which grow rapidly up to many metres in height, furnish screens and windbreaks, and the young shoots are eaten as a vegetable. Reeds, robust rhizomatous aquatic grasses, are an important sustainable resource of temperate and tropical wetlands. In central Africa experiments are in progress to use briquettes of compressed reeds as fuel. The roots of reeds mop up nutrients in water, and in Britain and elsewhere small reed-beds have been planted to purify domestic sewage.