Rhododendron subg. Hymenanthes
Rhododendron subg. Hymenanthes is a subgenus of the genus Rhododendron, with a widespread distribution in the temperate Northern Hemisphere. The species are evergreen shrubs and small to medium-sized trees, with medium-sized to large leaves. The flowers are large, produced in terminal trusses of 5-40 together.
The subgenus includes two sections, Rhododendron sect. Ponticum, divided into 24 subsections and about 140 species, and Rhododendron sect. Pentanthera.
Cultivation
This subgenus includes the majority of the larger evergreen rhododendrons widely grown as ornamental plants. Some species, notably Rhododendron ponticum, have escaped from cultivation and become invasive in some regions such as New Zealand.Ponticum
Section Ponticum includes:- R. subsect. Arborea R. subsect. Argyrophylla R. subsect. Barbata
- R. subsect. Campanulata R. subsect. Campylocarpa R. subsect. Falconera
- R. subsect. Fortunea R. subsect. Fulgensia
- R. subsect. Fulva R. subsect. Glischra
- R. subsect. Grandia R. subsect. Griersoniana R. subsect. Irrorata R. subsect. Lanata R. subsect. Maculifera R. subsect. Neriiflora R. subsect. Parishia
- R. subsect. Pontica R. subsect. Selensia R. subsect. Taliensia R. subsect. Thomsonia R. subsect. Venatora R. subsect. ''Williamsiana''
Arborea
Rhododendron subsect. Arborea is a subsection of section Ponticum in Hymenanthes consisting of 4 species of trees native to East Asia.Argyrophylla
Rhododendron subsect. Argyrophylla is a subsection of section Ponticum in Hymenanthes consisting of 23 species of shrubss native to East Asia. This section is distinguished by its silvery white, pale yellow or yellowish-brown hairs on the abaxial leaf surface.Barbata
Rhododendron subsect. Barbata is a subsection of section Ponticum in Hymenanthes consisting of 5 species of small trees native to East Asia.Campanulata
Rhododendron subsect. Campanulata is a subsection of section Ponticum in Hymenanthes consisting of 2 species of shrubs native to East Asia.| Image | Name | Distribution |
| Rhododendron campanulatum | China, Bhutan, India, Nepal | |
| Rhododendron gannanense | China |
Campylocarpa
Rhododendron subsect. Campylocarpa is a subsection of section Ponticum in Hymenanthes consisting of 6 species of shrubs with campanulate shaped flowers native to East Asia.| Image | Name | Distribution |
| Rhododendron callimorphum | China, Myanmar | |
| Rhododendron campylocarpum | China Bhutan, India, Myanmar, Nepal, | |
| Rhododendron henanense | China | |
| Rhododendron longicalyx | China | |
| Rhododendron souliei | China | |
| Rhododendron wardii | China |
Falconera
Rhododendron subsect. Falconera is a subsection of section Ponticum in Hymenanthes consisting of 14 species of shrubs and trees with thick leaves that have yellow veins and red brown hairs on the underside that are native to East Asia.| Image | Name | Distribution |
| Rhododendron arizelum | China, Myanmar | |
| Rhododendron basilicum | China, Myanmar | |
| Rhododendron coriaceum | China | |
| Rhododendron falconeri | Nepal, India, Bhutan | |
| Rhododendron fictolacteum | China, Myanmar | |
| Rhododendron galactinum | China | |
| Rhododendron hodgsonii | China, Bhutan, India, Nepal | |
| Rhododendron mechukae | India | |
| Rhododendron preptum | China, Myanmar | |
| Rhododendron rex | China Myanmar | |
| Rhododendron rothschildii | China | |
| Rhododendron semnoides | China | |
| Rhododendron sinofalconeri | China, Vietnam | |
| Rhododendron titapuriense | India |
Fortunea
Rhododendron subsect. Fortunea is a subsection of section Ponticum in Hymenanthes consisting of 37 species of shrubs or trees native to East Asia.Fulgensia
Rhododendron subsect. Fulgensia is a subsection of section Ponticum in Hymenanthes consisting of 3 species of shrubs with glossy leaves that have dark brown hairs on the underside native to East Asia.| Image | Name | Distribution |
| Rhododendron fulgens | China, Bhutan, India, Nepal | |
| Rhododendron miniatum | China | |
| Rhododendron rawatii | India |
Fulva
Rhododendron subsect. Fulva is a subsection of section Ponticum in Hymenanthes comprising 2 species of shrubs native to East Asia.| Image | Name | Distribution |
| Rhododendron fulvum | China, Myanmar | |
| Rhododendron uvariifolium | China |
Glischrum
Rhododendron subsect. Glischrum is a subsection of section Ponticum in Hymenanthes comprising 9 species of shrubs native to East Asia.| Image | Name | Distribution |
| Rhododendron adenosum | China | |
| Rhododendron crinigerum | China | |
| Rhododendron diphrocalyx | China | |
| Rhododendron glischroides | Myanmar | |
| Rhododendron glischrum | China India, Myanmar | |
| Rhododendron habrotrichum | China, Myanmar | |
| Rhododendron recurvoides | Myanmar | |
| Rhododendron spilotum | Myanmar | |
| Rhododendron vesiculiferum | China, Myanmar |
Grandia
Rhododendron subsect. Grandia is a subsection of section Ponticum in Hymenanthes that comprises 15 species of trees with large leaf blades covered with trichomes native to East Asia.Griersoniana
Rhododendron subsect. Griersoniana is a subsection of section Ponticum in Hymenanthes that contains a single species of shrub.| Image | Name | Distribution |
| Rhododendron griersonianum | China, Myanmar |
Maculifera
Rhododendron subsect. Maculifera is a subsection of section Ponticum in Hymenanthes that contains 15 species of shrubs or small trees with tomentose stems and rough bark.| Image | Name | Distribution |
| Rhododendron anwheiense | China | |
| Rhododendron longesquamatum | China | |
| Rhododendron maculiferum | China | |
| Rhododendron morii | Taiwan | |
| Rhododendron ochraceum | China | |
| Rhododendron pachyphyllum | China | |
| Rhododendron pachysanthum | Taiwan | |
| Rhododendron pachytrichum | China | |
| Rhododendron pilostylum | China | |
| Rhododendron polytrichum | China | |
| Rhododendron pseudochrysanthum | Taiwan | |
| Rhododendron sikangense | China | |
| Rhododendron strigillosum | China | |
| Rhododendron subroseum | China | |
| Rhododendron ziyuanense | China |
Lanata
Rhododendron subsect. Lanata contains 6 species of small trees found in east asiaParishia
Rhododendron subsect. Parishia is a subsection of section Ponticum in Hymenanthes that contains 8 species of small trees found in east asia.| Image | Name | Distribution |
| Rhododendron elliottii | India, Assam | |
| Rhododendron facetum | China, Myanmar, Vietnam | |
| Rhododendron flavoflorum | China | |
| Rhododendron huidongense | China | |
| Rhododendron kyawii | China, Myanmar | |
| Rhododendron parishii | Myanmar | |
| Rhododendron schistocalyx | China | |
| Rhododendron urophyllum | China |
Pontica
Rhododendron subsect. Pontica is a subsection of section Ponticum in Hymenanthes consisting of 13 species of shrubs to small trees native to North America, Europe, and East Asia.Selensia
Rhododendron subsect. Selensia is a subsection of section Ponticum in Hymenanthes consisting of 8 species of shrubs to small trees with campanulate flowers.Taliensia
Rhododendron subsect. Taliensia is a subsection of section Ponticum in Hymenanthes consisting of 57 species of shrubs and small trees with their leaves covered with indumentum.Thomsonia
Rhododendron subsect. Thomsonia is a subsection of section Ponticum in Hymenanthes consisting of 17 species of small trees with reddish flowers and peeling red bark native to East Asia.| Image | Name | Distribution |
| Rhododendron bonvalotii | China | |
| Rhododendron cerasinum | China, Myanmar | |
| Rhododendron cyanocarpum | China | |
| Rhododendron eclecteum | China, Myanmar | |
| Rhododendron eurysiphon | China | |
| Rhododendron faucium | China | |
| Rhododendron hookeri | China, India | |
| Rhododendron hylaeum | China, Myanmar | |
| Rhododendron meddianum | China, Myanmar | |
| Rhododendron megalanthum | China | |
| Rhododendron populare | China | |
| Rhododendron ramipilosum | China | |
| Rhododendron sherriffii | China | |
| Rhododendron stewartianum | China, Myanmar | |
| Rhododendron subansiriense | Bhutan, India | |
| Rhododendron thomsonii | China, Bhutan, India, Nepal, | |
| Rhododendron viscidifolium | China |
Williamsiana
Rhododendron subsect. Williamsiana is a subsection of section Ponticum in Hymenanthes consisting of 2 species| Image | Name | Distribution |
| Rhododendron venator | China | |
| Rhododendron leishanicum | China |
Pentanthera
Rhododendron sect. Pentanthera is a section of subgenus Hymenanthes in the genus Rhododendron. It comprises 15-16 species of deciduous shrubs native to temperate regions of the Northern Hemisphere.It includes two subsections:
- Pentathera
- Sinensia
Pentanthera
Species include:| Image | Name | Distribution |
| Rhododendron alabamense Alfred Rehder, 1921 | United States | |
| Rhododendron arborescens John Torrey, 1824 | United States | |
| Rhododendron atlanticum Alfred Rehder, 1921 | United States | |
| Rhododendron austrinum Rehder 1917 | United States | |
| Rhododendron calendulaceum John Torrey, 1824 | United States | |
| Rhododendron canadense Torr. | Canada in Newfoundland and extends into eastern Ontario and the United States from New York, New Jersey, and at high altitudes in the Appalachian Mountains further south to Pennsylvania. | |
| Rhododendron canescens Sweet 1889 | United States | |
| Rhododendron colemanii Ronald F. Miller, 2008 | United States | |
| Rhododendron cumberlandense Emma Lucy Braun, 1941 | United States | |
| Rhododendron eastmanii Kathleen Anne Kron, 1999 | United States | |
| Rhododendron flammeum Sarg. 1917 | United States | |
| Rhododendron luteum Sweet 1911 | southern Russia; and in Asia | |
| Rhododendron occidentale Torr. & A.Gray 1876 | United States | |
| Rhododendron periclymenoides Shinners 1962 | United States | |
| Rhododendron prinophyllum Millais 1917 | Eastern United States | |
| Rhododendron prunifolium Millais 1917 | United States | |
| Rhododendron viscosum Torr. 1824 | Eastern United States |
Sinensia
Species include:| Image | Name | Distribution |
| Rhododendron molle | S. China | |
| Rhododendron japonicum | Japan. |
The section is closely related to sect. Rhodora, differing from it in the flower corolla having five fully developed lobes, whereas sect. Rhodora has the upper three lobes joined into a single three-lipped lobe.