Ulva intestinalis


Ulva intestinalis is a green alga in the family Ulvaceae, known by the common names sea lettuce, gutweed and grass kelp. Until they were reclassified by genetic work completed in the early 2000s, the tubular members of the sea lettuce genus Ulva were placed in the genus Enteromorpha.

Distribution

Generally world-wide. It can be found in Bering Sea near Alaska, Aleutian islands, Puget Sound, Japan, Korea, Mexico, Philippines,and Russia. Besides this, places it can be found in Israel, and in such European countries as Azores, Belgium, Denmark, Ireland, Norway, Poland, and in such seas as the Baltic, and Mediterranean Sea. It is also found in the shores of the Pacific Ocean including in New Zealand.

Description

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. The species may be long and wide. They have rounded tips as well.
The algae may be reproductive at all times of the year. The life-history shows an alteration of generations, isomorphic - gametophytic and sporophytic.
In some references the species is treated as two subspecies: ssp. intestinalis Link and ssp. compressa Link.

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