[4] It can be found in Bering Sea near Alaska, Aleutian islands, Puget Sound, Japan, Korea, Mexico, Philippines, and Russia.

[6][7] The fronds have branches and are completely tubular expanding in width to mid-thallus, reaching 15 cm long or more.

The cells are irregularly arranged and the chloroplast is hood-shaped and placed to one side, generally with only one pyrenoid.

[8] The alga may be reproductive at all times of the year, and has a life-cycle with alternation of generations, in which the gametophyte and sporophyte are isomorphic, having identical morphology.

[4] In some references the species (Ulva intestinalis) is treated as two subspecies: ssp.