Description from Flora of China
Juncus takasagomontanus Satake.
Plants perennial, tufted, 5--20 cm tall. Stems terete or angled, slender. Basal and cauline leaves 3 or 4; leaf blade filiform, ± compressed, basal ones slightly shorter to longer than stem. Inflorescences terminal; head solitary, 2- or 3-flowered; bracts ovate; basal bract ca. 4 × 3 mm. Flowers sessile. Perianth segments greenish, linear, 4.5--6 mm, unequal with inner ones longer than outer, apex obtuse. Stamens 6; filaments 5--6 mm; anthers ca. 1.7 mm. Style very short; stigmas ca. 1.3 mm. Capsule yellowish to light brown, obovoid-ellipsoid, 5--6 mm, 1-loculed. Seeds ca. 0.5 mm, both ends appendaged; appendages white, caudate.
This species is closely related to Juncus maximowiczii and J. modicus. The type of J. triflorus has not been seen by the present authors.
* Wet places in mountains. C Taiwan.