Cymbopogon citratus; seréh, serai. Fresh lemon grass can be bought in most large towns in the West, and is usually to be preferred to dried or powdered forms, though these will do well enough. It is worth trying to get a stem to root; it makes an attractive house plant.
To make a lemon grass brush, cut off and discard about 1 cm/½ inch from the hard root-end of a stem of fresh lemon grass. Beat the cut end, not too hard, with the handle of a knife or a steak hammer until the fibres fray and make a flexible brush. Use this to brush on sauces while grilling or barbecuing; it will give a delicious extra aroma instead of the smell of roasting nylon.