Genus of 5-6 species of tufted, rhizomatous and tuberous, evergreen or semi-evergreen perennials, found in usually acidic woodland habitats in China, Vietnam, Taiwan and Japan. They have arching, linear, grass-like radical leaves, forming dence clumps or mats. Small, ovoid to spherical flowers, opening only slightly, are clustered in short, dence spikes or racemes, and are followed by black berries.