Vegetable gelatin is manufactured from a seaweed, genus Laminaria; from the tengusa, an American seaweed, and from Irish moss.

Some of the Laminariæ which form a belt around our own coasts not seldom attain a length of from eight to twelve feet.

The brown seaweed Laminaria digitata, ubiquitous in the coastal Pacific waters off Japan, absorbs iodine to help defend itself against environmental stresses such as pollution.