| Meiracyllium wendlandii Rchb. f., 1866 |
| Mesadenella Pabst & Garay, 1952 |
| Mesadenella petenensis (L.O. Williams) Garay, 1982 |
| Mesadenella tonduzii (Schltr.) Pabst & Garay, 1953 |
| Mesadenus Schltr., 1920 |
| Mesadenus affinis (C. Schweinf.) Garay, 1982 |
| Mesadenus chiangii (M.C. Johnst.) Garay, 1982 |
| Mesadenus galeottianus (A. Rich. & Galeotti) Schltr., 1920 |
| Mesadenus lucayanus (Britton) Schltr., 1920 |
| Mesadenus minutiflorus (A. Rich. & Galeotti) Schltr., 1920 |
| Mesadenus polyanthus (Rchb. f.) Schltr., 1920 |
| Mesadenus tenuissimus (L.O. Williams) Garay, 1982 |
| Mesicera Raf., 1825 |
| Mesicera michauxii (Nutt.) Raf., 1837 |
| Mesicera quinqueseta (Michx.) Raf., 1825 |
| Mesoglossum Halb., 1982 |
| Mesoglossum londesboroughianum (Rchb. f.) Halb., 1982 |
| Mexicoa Garay, 1974 |
| Mexicoa ghiesbreghtiana (A. Rich. & Galeotti) Garay, 1974 |
| Mexipedium V.A. Albert & M.W. Chase, 1992 |