Herbs; nodes with 2 rows of 3--5 roots. Leaves: sheath 6.5--55 cm, margins overlapping; blade to 2 m ´ 0.5--1.5 mm, margins entire, apex notched to rounded or slightly apiculate; veins 3. Generative shoots 50--60 cm, nodes 4--6, proximal 2 nodes each with 1 leaf, sterile, distal 2--4 nodes each bearing 1 leaf and 1--5 spathes. Inflorescences: peduncles 8--45 ´ 1--2 mm; staminate bract 2.5--4.3 ´ 2--2.7 mm; pistillate bract 3.5--6 ´ 1--1.5 mm, base distally narrowed, apex obtuse to acute. Fruits 2.8--3.2 ´ 2.9--3.5 mm.

Flowering and fruiting spring--fall. Intertidal zone; -15 m; B.C.; Calif., Oreg.; Mexico (Baja California).