Sea Lettuce, Aosa, Green Laver

Ulva fenestrata, Ulva lactuca

Color: Green (Bright)
Shape: Sheet
Texture: Smooth, often with holes like Swiss-cheese
Size: 4–12”+
Zone: Intertidal
Range: Alaska to California (Ulva fenestrata), World-wide (Ulva lactuca and other species)

Description: Bright green thin, lettuce-like “leaves” attached in tufts to a small holdfast. May be white at the edges. Several similar species. Some have holes like Swiss-cheese. Can be long or round. Prefers calm areas.

Edibility: Makes a tasty fresh salad.

Distinctive characteristics:

Collection notes: If sea lettuce populations are particularly profuse or dominant, check to be sure the area is free of sewage drainage or other pollution before collecting as sea lettuce grows particularly well in these conditions. Rinse with water to remove small sea creatures such as snails hiding in the blades.

Phylum: Chlorophyta (Green Algae)
Previous names:
Similar species: Easy to confused with Monostroma. Monostroma is only one cell layer thick while Sea Lettuce is two cell layers thick. Monostroma grows in a circle around a disc-shaped holdfast; Sea Lettuce has a short stipe growing up out of the holdfast. Also similar to other Ulva species. All are edible.

Leave a Reply