| Asteraceae | |
Otopappus acuminatus
| S. Watson | Proc. Amer. Acad. Arts 26: 140–141 | 1891 |
| Asteraceae | |
Otopappus alternifolius
| B.L. Rob. | Proc. Amer. Acad. Arts 26: 165–166 | 1891 |
| Asteraceae | |
Otopappus aschenbornii
| Klatt | Ann. K. K. Naturhist. Hofmus. 9: 362 | 1894 |
| Asteraceae | |
Otopappus asperulus
| S.F. Blake | Contr. U.S. Natl. Herb. 24(1): 30–31, t. 10 (photo) | 1922 |
| Asteraceae | |
Otopappus australis
| S.F. Blake | Contr. U.S. Natl. Herb. 20(13): 538–539, t. 45 | 1924 |
| Asteraceae | |
Otopappus brevipes
| B.L. Rob. | Proc. Amer. Acad. Arts 44(21): 621–622 | 1909 |
| Asteraceae | |
Otopappus calarcanus
| S. Díaz | Revista Acad. Colomb. Ci. Exact. 18(71): 480–482, f. 1 | 1993 |
| Asteraceae | |
Otopappus cordatus
| S.F. Blake | J. Washington Acad. Sci. 18: 28 | 1928 |
| Asteraceae | |
Otopappus curviflorus
| (R. Br.) Hemsl. | Biol. Cent.-Amer., Bot. 2(8): 191 | 1881 |
| Asteraceae | |
Otopappus epaleaceus
| Hemsl. | Biol. Cent.-Amer., Bot. 2(8): 191 | 1881 |
| Asteraceae | |
Otopappus ferrugineus
| V.M. Badillo | Ernstia 3: 4–7, f. 1–2 | 1981 |
| Asteraceae | |
Otopappus glabratus
| (J.M. Coult.) S.F. Blake | J. Bot. 53(632): 234–235 | 1915 |
| Asteraceae | |
Otopappus guatemalensis
| (Urb.) R.L. Hartm. & Stuessy | Syst. Bot. 8(2): 206 | 1983 |
| Asteraceae | |
Otopappus hirsutus
| (Sw.) R.L. Hartm. & Stuessy | Syst. Bot. 8(2): 205 | 1983 |
| Asteraceae | |
Otopappus imbricatus
| (Sch. Bip.) S.F. Blake | Contr. U.S. Natl. Herb. 26(5): 255 | 1930 |
| Asteraceae | |
Otopappus jaliscensis
| McVaugh | Contr. Univ. Michigan Herb. 9: 425, f. 31 | 1972 |
| Asteraceae | |
Otopappus koelzii
| McVaugh | Contr. Univ. Michigan Herb. 9(4): 425, f. 32 | 1972 |
| Asteraceae | |
Otopappus mexicanus
| (Rzed.) H. Rob. | Wrightia 6(3): 44 | 1979 |
| Asteraceae | |
Otopappus microcephalus
| S.F. Blake | J. Bot. 53: 232 | 1915 |
| Asteraceae | |
Otopappus oaxacanus
| (DC.) Klatt | Ann. K. K. Naturhist. Hofmus. 9(3): 362 | 1894 |
| Asteraceae | |
Otopappus olivaceus
| (Klatt) Klatt | Ann. K. K. Naturhist. Hofmus. 9(3): 362 | 1894 |
| Asteraceae | |
Otopappus perymenioides
| (Sch. Bip. ex Klatt) Klatt | Ann. Naturhist. Hofmus. Wien 9: 362 | 1894 |
| Asteraceae | |
Otopappus pittieri
| (Greenm.) B.L. Turner | Phytologia 69: 15 | 1990 |
| Asteraceae | |
Otopappus pringlei
| (Greenm.) S.F. Blake | J. Bot. 53: 232 | 1915 |
| Asteraceae | * |
Otopappus robinsonii
| Klatt | Ann. K. K. Naturhist. Hofmus. 9: 362 | 1894 |
| Asteraceae | |
Otopappus robustus
| Hemsl. | Biol. Cent.-Amer., Bot. 2(8): 191–192, t. 49 | 1881 |
| Asteraceae | |
Otopappus salazari
| S.F. Blake | Proc. Biol. Soc. Washington 32: 192 | 1919 |
| Asteraceae | |
Otopappus scaber
| S.F. Blake | Contr. U.S. Natl. Herb. 22(8): 636–637 | 1924 |
| Asteraceae | |
Otopappus serboana
| B.L. Turner | Phytologia 95(2): 156, f. 1, map 3 | 2013 |
| Asteraceae | |
Otopappus simplex
| V.M. Badillo | Bol. Soc. Venez. Ci. Nat. 10: 311 | 1946 |
| Asteraceae | |
Otopappus syncephalus
| Donn. Sm. | Bot. Gaz. 40(1): 6 | 1905 |
| Asteraceae | |
Otopappus tequilanus
| (A. Gray) B.L. Rob. | Proc. Amer. Acad. Arts 44: 622 | 1909 |
| Asteraceae | |
Otopappus trinervis
| S.F. Blake | J. Bot. 53(632): 231–232 | 1915 |
| Asteraceae | |
Otopappus verbesinoides
| Benth. | Hooker's Icon. Pl. 12: 47–48, t. 1153 | 1876 [1873] |
| Asteraceae | |
Otopappus xanthocarphus
| Brandegee | Univ. Calif. Publ. Bot. 3(8): 394–395 | 1909 |