Key to the Colombian species of Austroblechnum

1. Rachises abaxially covered with hairs...............................................................................................................................................2.

- Rachises glabrous or covered with scales .........................................................................................................................................3.

2. Rhizome scales with filiform apex; pinnae smooth abaxially................................................................................... A. aequatoriense

- Rhizome scales with acuminate apex; pinnae bullate abaxially........................................................................................ A. bullatum

3. Sterile laminae 33–82 × 9–32 cm, more than 22 pinnae pairs ..........................................................................................................4.

- Sterile laminae 11–34 × 2–9.5 cm, less than 15 pinnae pairs............................................................................................................5.

4. Fertile laminae 22–44 cm long; 22–28 pinnae pairs ........................................................................................................ A. divergens

- Fertile laminae 55–78 cm long; 25–46 pinnae pairs .......................................................................................................... A. wardiae

5. Fertile leaves petioles 3–10 cm long .................................................................................................................................................6.

- Fertile leaves petioles 14–24 cm long ...............................................................................................................................................7.

6. Laminae with 1–2 pairs of reduced pinnae; rhizome scales 3.5–4 mm long ................................................................ B. lherminieri

- Laminae without reduced pinnae, rhizome scales less than 3 mm long.......................................................................... A. ascendens

7. Sterile laminae 6.5–9 cm wide, base with 1–3 pairs of reduced pinna ........................................................................... A. organense

- Sterile laminae less than 6 cm wide, base with 3–12 pairs of reduced pinnae..................................................................................8.

8. Sterile laminae 3–6 cm wide, 3–8 pairs of auriculiform pinnae...................................................................................... A. lehmannii

- Sterile laminae less than 2.5 cm wide, 8–12 pairs of auriculiform pinnae.................................................................. A. pinnatifidum