Nemalion vermiculare

Thallus simple, worm-shaped, cylindrical or slightly compressed, lubricous, soft, 10-22(-100) cm length, to 2 mm thick, dark wine-colored. Medulla multiaxial, composed of colorless filaments consisting of elongate cylindrical cells (5-6.5 μm diam.). Cortex composed of peripherical medullary cells consisting of radiating short pigmented branchlets immersed in mucilaginous layer. Sporangial plants microscopic of uniserial branched filaments bearing cruciate tetrasporangia. Gonimoblasts develop in cortex. Growing on intertidal rocks, often forming narrow belts at sites exposed to moderate and strong wave action.

Temperate and subtropical waters of Pacific Ocean. In countries of the Asia-Pacific Region: China, Japan, Korea, Russia (the Sea of Japan, Peter the Great Bay, Kuriles, Sakhalin and Moneron Islands).