Racomitrium japonicum

Sunagoke Moss, Japanese Rock Moss, Sand Moss

A hardy, drought-tolerant moss widely used for green roofs in Japan. It forms dense, dull green to yellowish-green mats of irregularly branched stems (2–5 cm tall) with papillose leaves that curl inward when dry. Papillose means the leaf surface is covered in tiny bumps, which help trap moisture from the air. Tolerant of heat, drought, and low nutrients, it is one of the few mosses suited to open terrariums and drier setups where good air circulation matters. Now reclassified as Niphotrichum japonicum.