Hemp

The Hemp plant can be used for a number of useful things such as, fibre production, biomass diesel (it is one of the best biomass plants).

It is related to, but not the same as, marijuana and doesn't produce and noticable quantity of psychoactive substances. Its relationship to marijuana has however meant that its growth in most first world countries is outlawed (or very tightly controlled).

Much of the campaigning against idustrial hemp (in the USA) was by the president of the DuPont corporation whos business was under threat by hemps benifits over synthetic materials (although the DuPont corporation did produce some hemp based products).