| Ruehssia mollis (Brandegee) L.O. Alvarado, 2021 |
| Ruehssia neriifolia (Decne.) L.O. Alvarado, 2021 |
| Ruehssia oaxacana (Morillo) L.O. Alvarado, 2021 |
| Ruehssia parvifolia (Brandegee) L.O. Alvarado, 2021 |
| Ruehssia popoluca (Juárez-Jaimes & A. Campos) L.O. Alvarado, 2021 |
| Ruehssia pringlei (S. Watson) L.O. Alvarado, 2021 |
| Ruehssia propinqua (Hemsl.) L.O. Alvarado, 2021 |
| Ruehssia rzedowskiana (Juárez-Jaimes & W.D. Stevens) L.O. Alvarado, 2021 |
| Ruehssia salaschiblii (L.O. Alvarado & K. Maya M.) K. Maya M., 2021 |
| Ruehssia schlechteriana (W. Rothe) L.O. Alvarado, 2021 |
| Ruehssia stephanotidifolia (Woodson) L.O. Alvarado, 2021 |
| Ruehssia stevensiana (Juárez-Jaimes) L.O. Alvarado, 2021 |
| Ruehssia steyermarkii (Woodson) L.O. Alvarado, 2021 |
| Ruehssia sumiderensis Lozada-Pérez, Ram.-Mar. & Gonz.-Martínez, 2020 |
| Ruehssia tholiformis (Juárez-Jaimes & L.O. Alvarado) L.O. Alvarado, 2021 |
| Ruehssia trivirgulata (Bartlett) L.O. Alvarado, 2021 |
| Ruehssia tubularis (L.O. Williams) L.O. Alvarado, 2021 |
| Ruehssia veronicae (W.D. Stevens) L.O. Alvarado, 2021 |
| Ruehssia zimapanica (Hemsl.) L.O. Alvarado, 2021 |
| Rytidoloma Turcz., 1852 |