| Xylorhiza orcuttii (Vasey & Rose) Greene, 1896 |
| Xylorhiza wrightii (A. Gray) Greene, 1896 |
| Xylothamia G.L. Nesom, 1990 |
| Xylothamia diffusa (Benth.) G.L. Nesom, 1990 |
| Xylothamia johnstonii G.L. Nesom, 1990 |
| Xylothamia palmeri (A. Gray) G.L. Nesom, 1990 |
| Xylothamia parrasana (S.F. Blake) G.L. Nesom, 1990 |
| Xylothamia pseudobaccharis (S.F. Blake) G.L. Nesom, 1990 |
| Xylothamia purpusii (Brandegee) G.L. Nesom, 1990 |
| Xylothamia riskindii (B.L. Turner & G. Langford) G.L. Nesom, 1990 |
| Xylothamia triantha (S.F. Blake) G.L. Nesom, 1990 |
| Xylothamia truncata G.L. Nesom, 1992 |
| Xylovirgata Urbatsch & R.P. Roberts, 2004 |
| Xylovirgata pseudobaccharis (S.F. Blake) Urbatsch & R.P. Roberts, 2004 |
| Youngia Cass., 1831 |
| Youngia japonica (L.) DC., 1838 |
| Zaluzania Pers., 1807 |
| Zaluzania anthemidifolia B.L. Rob. & Greenm., 1889 |
| Zaluzania augusta (Lag.) Sch. Bip., 1861 |
| Zaluzania augusta var. augusta (Lag.) Sch. Bip., 1861 |