| Chionolaena lavandulifolia (Kunth) Benth. & Hook. f. ex B.D. Jacks., 1893 |
| Chionolaena macdonaldii (G.L. Nesom) G.L. Nesom, 2001 |
| Chionolaena mexicana S.E. Freire, 1993 |
| Chionolaena salicifolia (Bertol.) G.L. Nesom, 2001 |
| Chionolaena sartorii Klatt, 1887 |
| Chionolaena seemannii (Sch. Bip.) S.E. Freire, 1993 |
| Chlamysperma Less., 1832 |
| Chlamysperma arenarioides Hook. & Arn., 1837 |
| Chloracantha G.L. Nesom, 1991 |
| Chloracantha ortegae (S.F. Blake) G.L. Nesom, 2018 |
| Chloracantha spinosa (Benth.) G.L. Nesom, 1991 |
| Chloracantha spinosa var. jaliscensis (McVaugh) S.D. Sundb., 1991 |
| Chloracantha spinosa var. spinosa (Benth.) G.L. Nesom, 1991 |
| Chloracantha spinosa var. spinosissima (Brandegee) S.D. Sundb., 1991 |
| Chloracantha spinosissima (Brandegee) G.L. Nesom, 2018 |
| Chondrilla L., 1753 |
| Chondrilla pauciflora D. Don, 1830 |
| Chondrillinae (W.D.J. Koch) Lamotte, 1847 |
| Chorisiva Rydb., 1922 |
| Chromolaena DC., 1836 |