1 | Fertile leaflets distinctly narrower than sterile. |
1' | Fertile leaflets little different from sterile in size and shape. |
2 | Fertile pinnules deeply lobed; massive tree-ferns |
2' | Fertile pinnules not lobed; stem short, creeping |
3 | Pinnules deeply lobed almost at right angles to costa, not pinnate. |
3' | Pinnules pinnate, tertiary leaflets small, very oblique and lobed |