Family Description:
Characters are the same as described for the order. In contrast to the Galaxauraceae, members of the Liagoraceae lack an involucre (filaments surrounding the cystocarp) and a distinct ostiole (pore) through which carpospores are released.

Species description:
The gametophytic phase is composed of solid, erect, reddish brown, deep purple or golden brown cylinders. These are soft and rubbery in texture. They are rarely branched, and never near their tips. The cylinders are about 2-4 mm (about 0.1 to 0.2 in) in diameter and usually less than 20 cm (8 in) tall (Alaskan specimens are smaller still), but can reach 45 cm (18 in) in length. Plants often occur in clusters and are attached by a small, cushionlike holdfast to barnacles or rocks, usually on exposed coasts. This is truly a summer species, first appearing in late June, when it is usually too small to identify with certainty without the aid of a microscope, and disappearing by late September. The sporophytic phase of Rubber Threads is microscopic.

Source:  North Pacific Seaweeds

Synonyms and Alternate Names:
Fucus helminthoides
Nemalion lubricum