| Astragalus prorifer M.E. Jones, 1893 |
| Astragalus pueblae M.A. Jones, 1912 |
| Astragalus purpusii M.E. Jones, 1912 |
| Astragalus purpusii var. coccineus Parry, 1890 |
| Astragalus quinqueflorus S. Watson, 1886 |
| Astragalus racemosus Pursh, 1814 |
| Astragalus racemosus var. brevisetus M.E. Jones, 1895 |
| Astragalus racemosus var. racemosus Pursh, 1814 |
| Astragalus racemosus var. treleasei Ch. Porter, 1945 |
| Astragalus racemosus var. typicus Ch. Porter, 1945 |
| Astragalus radicans Hornem., 1815 |
| Astragalus radicans var. harshbergeri (Rydb.) Barneby, 1964 |
| Astragalus radicans var. radicans Hornem., 1815 |
| Astragalus regiomontanus Barneby, 1964 |
| Astragalus reptans Willd., 1809 |
| Astragalus rosei M.E. Jones, 1923 |
| Astragalus rupertii Villarreal & M.A. Carranza, 1994 |
| Astragalus rusbyi Greene, 1884 |
| Astragalus rusbyi var. longissimus M.E. Jones, 1895 |
| Astragalus sabulonum A. Gray, 1878 |