Scleranthus uniflorus forms a dense, mossy hummock 4 in (10 cm) or more across. The yellow to orange leaves are minute and overlap the stem. The flowers are minute and have 4 sepals.
Scleranthus uniflorus is found at sea level to subalpine and montane, in grassland and shrubland, also on sand, rocks or dry riverbeds, South Island, New Zealand. Its name means hard flowers.