| Cercocarpus paucidentatus (S. Watson) Britton, 1894 |
| Cercocarpus pringlei (C.K. Schneid.) Rydb., 1913 |
| Cercocarpus rotundifolius Rydb., 1913 |
| Cercocarpus rzedowskii Henrickson, 1987 |
| Cercocarpus treleasei C.K. Schneid., 1905 |
| Chamaebatia Benth., 1849 |
| Chamaebatia australis (Brandegee) Abrams, 1907 |
| Chamaemeles Lindl., 1821 |
| Chamaemeles mexicana Baill., 1869 |
| Cotoneaster Medik., 1789 |
| Cotoneaster denticulatus Kunth, 1824 |
| Cotoneaster lucidus Schltdl., 1854 |
| Cotoneaster nervosa Decne., 1874 |
| Cotoneaster pannosus Franch., 1890 |
| Cowania D. Don, 1824 |
| Cowania ericifolia Torr. ex A. Gray, 1853 |
| Cowania mexicana D. Don, 1825 |
| Cowania plicata D. Don, 1838 |
| Crataegus L., 1753 |
| Crataegus aria L., 1753 |