Enteromorpha flexuosa
Chlorophyta, Ulvaceae
Authority: (Wulfen ex Roth) J. Agardh
Hawaiian name: limu `ele`ele ('black seaweed')
Characteristic feature: Long green strands of flattened hollow tubes.
Description: Plants tubular, hollow, with tube walls one cell thick, to 8 cm tall (taller elsewhere), axes 1-7 mm wide, unbranched, or branched at or near the base; branches cylindrical, becoming inflated, sometimes bent or flexuous. Cells in surface view arranged in short longitudinal rows in most parts of plants; cells small, 7-10 by 10-18 µm, with 1-2 (and more) pyrenoids.
Habitat: Attached to sandy high to mid-intertidal rocks, to 2 m deep, where freshwater enters the ocean; epiphytic in brackish fishponds.
Hawaiian distribution: All main Hawaiian Islands, including the Northwestern Hawaiian Islands.
Other: Indigenous to Hawai‘i. Can tolerate a wide range of salinities. Exhibits invasive characteristics in areas of fresh water intrusion and high nutrient input. Hawaiian name refers to the dark color of the prepared limu.