1. Conidiophores complex, mostly branched ………………………………………………………………………………………………………….. 2
1′. Conidiophores simple, unbranched …………………………………………………………………………………………………………………. 3
2. Conidia ellipsoidal, 3–5 × 1–2.5 µm ………………………………………………………………………… Magnaporthiopsis meyeri-festucae
2′. Conidia curved to lunate, 4–6 × 1 µm …………………………………………………………………………….. Magnaporthiopsis agrostidis
3. Conidia averaging ≥ 3 µm wide ……………………………………………………………………………………………………………………….. 4
3′. Conidia averaging < 3 µm wide ………………………………………………………………………………………………………………………. 7
4. Colony grey on PDA …………………………………………………………………………………………………….. Magnaporthiopsis maydis
4′. Colony dark-green on PDA ……………………………………………………………………………………………………………………………. 5
5. Associated with Triticum aestivum ………………………………………………………………………………….. Magnaporthiopsis rhizophila
5′. Associated with other hosts …………………………………………………………………………………………………………………. 6
6. Conidia 7–13 × 2–6.5 µm, associated with Agrostis, Cynodon, Festuca, and Poa sp. ………………… Magnaporthiopsis cynodontis
6′. Conidia 7.5–11.5 × 3.5–5 µm, associated with Panicum sp. …………………………………………………… Magnaporthiopsis panicorum
7. Crust-like proliferations of mycelium absent ………………………………………………………. Magnaporthiopsis poae (Type species)
7′. Crust-like proliferations of mycelium present …………………………………………………………………….. Magnaporthiopsis incrustans