Tufted to mat-forming, glabrous, 5-12cm high. Leaves linear-elliptic to linear-obovate 4-7mm long, densely arranged towards the tips of the stems. Inflorescences branching, corymbose cymes. Flowers many, yellow, five-petalled, 8-10mm wide. Japan, on rocks near the sea. Mainly due to the diligent collecting of Y. Ochi, European collections have been furnished with several unusual, regional variations. S.o. 'Jogashima Island' is a large, very succulent form which must be grown outdoors in the summer to retain its red-suffused, upright growth. S.o. 'Minor' has tiny, flat, very narrow linear leaves 3 by 0.8mm on tangled stems which form a dense, wine-red hummock; flowers only produced in small numbers on each inflorescence. This form appears as close to the mountain form of S. japonicum as it does to the type species of S. oryzifolium, so its place here is rather tentative.