Algy

Alga is the latin for seaweed, ok. The two varieties found most often in the caribbean are sargassum natons and sargassums fluitons. These macro algies that we see in these types of seaweed have more complex structures than land plants. So they might have something that is akin to the stalk of a land plant and something that's akin to the leaves. In these cases, they would be algal fronds.