clams
Clams come in lots of sizes, a few shapes and many varieties.
What are they? Bivalves, most of which have the familiar clam shape, although some are more elongated. They range in size from geoducks (which weigh about a kilo or more) down to tiny clams about 1cm long. The delicious, tender bamboo clams are long and thin, resembling the plant they're named after.
What are the differences? In general, smaller clams are more tender and easier to prepare - you can basically just cook and eat them; unlike with the larger varieties, it isn't necessary to remove the stomach and other parts. Smaller clams can be eaten whole, while larger ones are usually chopped.
What to look for: clams should be alive and spitting - literally: they squirt water from their necks. They should be displayed in tubs of water. Don't buy clams that look dried out and avoid ones with broken shells.
How are they available? For most preparations, fresh is best. Clam meat is also sold in cans or frozen and made into convenience foods, such as soup and battered, deep-fried clam strips.
In Chinese cuisine, tiny clams (less than 1cm) are preserved and used in a wonderfully salty, tangy concoction, which is used as a dipping sauce for deep-fried fish balls and boiled pig's trotters.