Resembling miniature cacti, marsh samphire is sometimes sold in reputable fishmongers, but by far the best way to get hold of these hardy plants is to pick-your-own at low tide. Take along a pair of wellington boots - it's a muddy, but rewarding job. One of the best places to forage for samphire is on the Norfolk coast.
A rare plant, related to parsley and fennel. It has an earlier season than marsh samphire, and is in season during spring, rather than summer. Aficionados swear by the superior flavour, but it's hard to find, and marsh samphire with its characteristic saltiness makes a fine alternative.