| Hexalectris warnockii Ames & Correll, 1943 |
| Hexisea Lindl., 1834 |
| Hexisea bidentata Lindl., 1834 |
| Hexisea bidentata var. imbricata (Lindl.) C. Schweinf., 1952 |
| Hexisea imbricata (Lindl.) Rchb. f., 1862 |
| Hexisea oppositifolia (A. Rich. & Galeotti) Rchb. f., 1862 |
| Hexisea tenuissima H. Wendl. & Kraenzl., 1900 |
| Hintonella Ames, 1938 |
| Hintonella mexicana Ames, 1938 |
| Homalopetalum Rolfe, 1896 |
| Homalopetalum costaricense Schltr., 1923 |
| Homalopetalum kienastti (Rchb. f.) Withner, 1998 |
| Homalopetalum pachyphyllum (L.O. Williams) Dressler, 1964 |
| Homalopetalum pumilio (Rchb. f.) Schltr., 1923 |
| Homalopetalum pumilum (Ames) Dressler, 1964 |
| Hormidium Lindl. ex Heynh., 1841 |
| Hormidium boothianum (Lindl.) Brieger, 1960 |
| Hormidium brassavolae (Rchb. f.) Brieger, 1977 |
| Hormidium guttatum (A. Rich. & Galeotti) Brieger, 1977 |
| Hormidium humile (Cogn.) Schltr., 1920 |