Although some siphonous green algae (order Bryopsidales) can stand three feet tall, each is composed of a single, huge cell. Within, millions of nuclei, chloroplasts and mitochondria move about freely. This single-compartment architecture might suggest that such plants are particularly vulnerable to injury. In fact, these algae are quite robust: A plant can plug a wound in seconds and will in short order regenerate the lost tissue. Many species can even use a small bit of excised tissue to regenerates the rest of the plant. The ability to reproduce in this way offers these algae considerable competitive advantage over other marine organisms. In some settings where they have been accidentally introduced, notably the Mediterranean Sea, certain species of siphonous green algae have proved all too successful, displacing native marine flora over large areas.