They exhibit either a distichous pinnate structure or irregularly, partially bipinnate arrangements. The primary axes lack outer coverings (ecorticate) and consist of a central axial cell. The horizontal axes do not have stipules and are dorsiventral, expanding through transverse divisions of their leading cells. These axes are cylindrical, branching out laterally at irregular intervals to create upright axes and additional horizontal axes. They often generate extra branches known as adventitious branches. The fronds have a linear shape. The plants are colored dark red to black, growing in tufts and having a soft or firm texture.