Bracken, or Brake, the common English name for Pteris aquilina, the commonest fern of Northern Europe, which is also widely distributed in temperate and tropical regions. It occurs on heaths and moors and in forests, with a creeping rhizome, tough tripinnate or quadripinnate erect fronds, 1 to 10 feet high, and sori or clusters of sporangia all along the recurved under margin of the pinnules. As these sporangia lie between two indusia or membranes, the species may have to be transferred to the genus Pasia. The complicated bands of dark selerenchymatous tissue in the stem and leaf-stalks are popularly known as King Charles's oak. At the primary trifurcation of the fronds there are in the young stage glands exuding honey which attract ants. Bracken is the badge of the clan Robertson.