Family Description:
Members of this family have bodies that are either tubular and one cell thick or bladelike and two cell layers thick. Most cells contain a single nucleus and a single chloroplast. The chloroplast is flattened to cuplike in shape, and has one to several pyrenoids.
Typically, the alternation of generations shown by members of this family is isomorphic, with sporophytic generations similar to gametophytic generations. When asexual spores are formed, they are motile and bear four flagella. Gametes are biflagellate.

Species description:
Green String Lettuce almost always grows on rocks in protected bays and is widely distributed throughout the world. It also grows as an epiphyte on Bull Kelp (Nereocystis luetkeana). It resembles Ulva but is somewhat narrower. It is tubular only at the base; the upper part of the bright green blade is about 2 cm (0.8 in) wide in our area and is strongly ruffled along the edges.

Source:  North Pacific Seaweeds

Synonyms and Alternate Names:
Enteromorpha linza