E. crassipes

Water hyacinth (E. crassipes) roots (dried) sorbent Al Rmalli et al. (2005)... 

Chigbo, F.E., R.W. Smith, and F.L. Shore. 1982. Uptake of arsenic, cadmium, lead and mercury from polluted waters by the water hyacinth Eichhomia crassipes. Environ. Pollut. 27A 31-36. 

The water hyacinth Eichhornia crassipes originates from Brazil, and although it represents one of the most troublesome and invasive of water weeds, it is also one of the best phytoremediants of polluted water. The biomass becomes saturated with pollutants, which can then be removed from the water by harvest of the biomass and its composting, a process which achieves a substantial reduction in the mass requiring further processing (e.g., incineration under controlled conditions). The species is highly susceptible to frost, but in frost-free environments, its introduction is risky as it can readily become uncontrollable. 

Wood ashes.—The ash of wood, not coal, contains about 30 per cent, of potassium carbonate. Prior to the exploitation of the Stassfurt salts about the middle of the nineteenth century, the chief source of potash was wood ashes, and the process is still used in certain localities where wood-fuel is employed and where much waste wood is available—e.g. in some parts of Canada, United States, Russia, Spain, etc. The ash of trees, hedge-cuttings, sawdust, etc., can be made to yield potash.5 In the Caucasus, the sunflower is grown on waste land for the sake of its seed. The stalks, leaves, etc., are a by-product and are burnt the ash is used as a source of potash. Nearly 7000 tons per annum of crude potash from this source were exported from Novorossik in Russia. The residues in the manufacture of olive oil and almond shells are also stated by G. l Abate to be exceptionally rich in potash salts F. W. F. Day claims that the roots of the water hyacinth (eiehornia crassipes) have... 

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