Erica quadrangularis forms part of the Orophanes Section of the Erica genus, positioned in the Euerica subgenus of true heaths.

The pointed corolla lobes are conspicuous here on the white flowers, some with a hint of pink. Although the anthers are included inside the corolla, some of the widely open flowers facing the camera show that the anthers are dark.

The flowers are small, the leaves growing in fours on the upper stems behind them tiny (Baker and Oliver, 1967).