| Javieria venosa (Lindl.) Archila, Chiron & Szlach., 2013 |
| Karma Karremans, 2023 |
| Karma cedralensis (Ames) Karremans, 2023 |
| Karma dura (Lindl.) Karremans, 2023 |
| Kefersteinia Rchb. f., 1852 |
| Kefersteinia lactea (Rchb. f.) Schltr., 1923 |
| Kefersteinia tinschertiana Pupulin, 2004 |
| Kegeliella Mansf., 1934 |
| Kegeliella atropilosa L.O. Williams & A.H. Heller, 1964 |
| Kionophyton Garay, 1982 |
| Kionophyton pollardianum Szlach., Rutk. & Mytnik, 2004 |
| Kionophyton pyramidale (Lindl.) Garay, 1982 |
| Kionophyton riodelayensis (Burns-Bal.) Catling, 1989 |
| Kionophyton sawyeri (Standl. & L.O. Williams) Garay, 1982 |
| Kionophyton seminuda (Schltr.) Garay, 1982 |
| Kionophyton seminudum (Schltr.) Garay, 1982 |
| Kraenzlinella Kuntze, 1904 |
| Kraenzlinella erinacea (Rchb. f.) Solano, 2003 |
| Kraenzlinella hintonii (L.O. Williams) Solano, 2003 |
| Kraenzlinella muricata (Schltr.) Rolfe, 1915 |