Specimen
Habitat
MP-0002 / 0024 โ Juncaceae
Juncus decipiens (Buchenau) Nakai
Igusa (JP)
The cylindrical, pith-filled rush behind Japan’s tatami โ a wetland herb woven into daily life.
Distribution
Widely distributed in East Asia, including Japan, Korea, China and Taiwan; cultivated in Japan for tatami matting.
Habitat
Wet meadows, marsh margins, paddy edges and other permanently moist, open ground.
Morphology
A densely tufted perennial herb with erect, slender, cylindrical culms filled with continuous white pith. Leaves are reduced to basal sheaths. Because the lowest involucral bract continues the line of the culm, the inflorescence appears to arise from its side (pseudolateral).
Botanical notes
Cultivated for centuries as the raw material of tatami and woven mats. The cylindrical, pith-filled culm is the structural basis of both its fragrance and its resilience when dried.
References
Taxonomy and distribution follow Plants of the World Online (Kew), YList (Yonekura & Kajita) and regional floras; CITES Species+ for trade status. Descriptions are provisional and are revised as specimens are verified.