| Rhododendron alabamense Rehder | | a | | Rhododendron alabamenseRehder | |
| Rhododendron atlanticum (Ashe) Rehder | | a | | Rhododendron atlanticum(Ashe) Rehder | |
| Rhododendron canadense (L.) Torr. | | a | | Rhododendron canadense(L.) Torr. | |
| Rhododendron canescens (Michx.) Sweet | | a | | Rhododendron canescens(Michx.) Sweet | |
| Rhododendron canescens (Michx.) Sweet var. candidum (Small) Rehder | Rhododendron canescens (Michx.) Sweet | | i | Rhododendron canescens(Michx.) Sweet var.candidum (Small) Rehder | Rhododendron canescens(Michx.) Sweet |
| Rhododendron flavum G. Don | Rhododendron luteum Sweet | | | Rhododendron flavumG. Don | Rhododendron luteumSweet |
| Rhododendron japonicum (A. Gray) Valck. Sur. | Rhododendron molle (Blume) G. Don subsp. japonicum (A. Gray) Kron | | | Rhododendron japonicum(A. Gray) Valck. Sur. | Rhododendron molle(Blume) G. Don subsp. japonicum (A. Gray) Kron |
| Rhododendron japonicum (A. Gray) Valck. Sur. var. glaucophyllum H. Hara ex Ohwi, nom. inval. | Rhododendron molle (Blume) G. Don subsp. japonicum (A. Gray) Kron | | i | Rhododendron japonicum(A. Gray) Valck. Sur. var.glaucophyllum H. Hara ex Ohwi, nom. inval. | Rhododendron molle(Blume) G. Don subsp. japonicum (A. Gray) Kron |
| Rhododendron ×kosterianum C. K. Schneid. | | a | | Rhododendron kosterianumC. K. Schneid. | |
| Rhododendron luteum Sweet | | a | | Rhododendron luteumSweet | |
| Rhododendron molle (Blume) G. Don | | a | | Rhododendron molle(Blume) G. Don | |
| Rhododendron nudiflorum Torr. | Rhododendron periclymenoides (Michx.) Shinners | | | Rhododendron nudiflorumTorr. | Rhododendron periclymenoides(Michx.) Shinners |
| Rhododendron nudiflorum Torr. f. glandiferum (Porter) Fernald | Rhododendron periclymenoides (Michx.) Shinners | | i | Rhododendron nudiflorumTorr. f. glandiferum (Porter) Fernald | Rhododendron periclymenoides(Michx.) Shinners |
| Rhododendron oblongifolium (Small) Millais | Rhododendron viscosum (L.) Torr. | | | Rhododendron oblongifolium(Small) Millais | Rhododendron viscosum(L.) Torr. |
| Rhododendron occidentale (Torr. & A. Gray) A. Gray | | a | | Rhododendron occidentale(Torr. & A. Gray) A. Gray | |
| Rhododendron prunifolium (Small) Millais | | a | | Rhododendron prunifolium(Small) Millais | |
| Rhododendron roseum Rehder | Rhododendron canescens (Michx.) Sweet | | | Rhododendron roseumRehder | Rhododendron canescens(Michx.) Sweet |
| Rhododendron viscosum (L.) Torr. var. glaucum Torr. | Rhododendron viscosum (L.) Torr. | | i | Rhododendron viscosum(L.) Torr. var.glaucum Torr. | Rhododendron viscosum(L.) Torr. |
| Rhododendron viscosum (L.) Torr. var. nitidum (Pursh) A. Gray | Rhododendron viscosum (L.) Torr. | | i | Rhododendron viscosum(L.) Torr. var.nitidum (Pursh) A. Gray | Rhododendron viscosum(L.) Torr. |
| Rhododendron viscosum (L.) Torr. f. rhodanthum Rehder | Rhododendron viscosum (L.) Torr. | | i | Rhododendron viscosum(L.) Torr. f. rhodanthum Rehder | Rhododendron viscosum(L.) Torr. |
| Rhododendron calendulaceum (Michx.) Torr. | | a | | Rhododendron calendulaceum(Michx.) Torr. | |
| Rhododendron arborescens (Pursh) Torr. | | a | | Rhododendron arborescens(Pursh) Torr. | |
| Rhododendron prinophyllum (Small) Millais | | a | | Rhododendron prinophyllum(Small) Millais | |
| Rhododendron viscosum (L.) Torr. | | a | | Rhododendron viscosum(L.) Torr. | |
| Rhododendron periclymenoides (Michx.) Shinners | | a | | Rhododendron periclymenoides(Michx.) Shinners | |
| Rhododendron roseum auct. | Rhododendron prinophyllum (Small) Millais | | | Rhododendron roseumauct. | Rhododendron prinophyllum(Small) Millais |
| Rhododendron austrinum (Small) Rehder | | a | | Rhododendron austrinum(Small) Rehder | |
| Rhododendron molle (Blume) G. Don subsp. japonicum (A. Gray) Kron | | a | i | Rhododendron molle(Blume) G. Don subsp. japonicum (A. Gray) Kron | |
| Rhododendron molle (Blume) G. Don subsp. molle | | a | i | Rhododendron molle(Blume) G. Don subsp. molle | |
| Rhododendron cumberlandense E. L. Braun | | a | | Rhododendron cumberlandenseE. L. Braun | |
| Rhododendron flammeum (Michx.) Sarg. | | a | | Rhododendron flammeum(Michx.) Sarg. | |
| Rhododendron colemanii R. F. Mill. | | a | | Rhododendron colemaniiR. F. Mill. | |