Herb
with milky sap; stems prostrate, pubescent, often red; leaves
opposite, simple, oblong-elliptic, margin toothed; flowers minute,
clustered into cup-like cyathia; cyathia borne in the leaf axils;
cyathial appendages 4, minute, rim-like extensions of the 4 glands;
capsules coarsely pubescent on the angles, the faces glabrous.