Schiedea trinervis is a species of flowering plant in the family Caryophyllaceae. It is called three nerved alsinidendron and is endemic to island of Oahu in Hawaii. It is a subshrub, reaching a height of .
Three-nerved alsinidendron inhabits mixed mesic and wet forests on the slopes of the Waianae Range at elevations of . Associated plants include pilo (Coprosma spp.), apeape (Gunnera petaloidea), alani (Melicope spp.), hÃÂpuu (Cibotium spp.), hame (Antidesma platyphyllum), and mÃÂmaki (Pipturus albidus). It is threatened by habitat loss.