Rhododendrons

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Rhododendrons
Rhododendron flower
Systematics
Asterids Order : Heather-like (Ericales) Family : Heather family (Ericaceae) Subfamily : Rhododendroideae Tribe : Rhododendreae Genre : Rhododendrons
Scientific name
rhododendron
L.

The rhododendrons (singular according to Duden: the or the rhododendron , from Greek ῥόδον = rhodon, the rose, and δένδρον = dendron, the tree) are a genus of plants from the heather family (Ericaceae). With around one thousand species, it is a comparatively large genus with a large number of groups of varieties and an almost unmanageable number of varieties, some of which are hybrids , some of which are select forms that can only be reproduced vegetatively (so-called sports ).

The distribution area extends from the seashore to the high mountains (in Tibet to over 5500 meters) and from the tropical rainforest to the subpolar tundra (for example Rhododendron lapponicum and Rhododendron camtschaticum ). The species and their demands are accordingly different.

description

Illustration of rhododendron ambiguum

Vegetative characteristics

Rhododendron species are predominantly evergreen shrubs , but there are also deciduous species, and some species are even trees . Some live optionally epiphytically on trees or epilithically on rocks, especially species of the Vireya section (syn. Schistanthe ), in mountain forests of the eastern Himalayas and mountain rainforests of the Indonesian islands.

The alternate leaves are arranged in a petiole and a leaf blade. The simple leaf blades are mostly entire.

Many species show a matted, copper (eg Rhododendron bureavii ) to silver-colored (for example Rhododendron argyrophyllum ) indumentum on the underside of leaves, some (eg. As Rhododendron fortunei , many azaleas ie deciduous rhododendrons as Rhododendron luteum , Rhododendron prinophyllum ) smell tender to strong, the shoots can be copper-colored ( Rhododendron williamsianum ) to blue ( Rhododendron aeruginosum ), and the leaves of many lepidotes are also fragrant. All these properties are lost when cruising.

Generative characteristics

The flowering time of the rhododendrons extends from January to August, most of them bloom in April / May. The reason for its popularity and great horticultural interest can be seen in this sometimes very magnificent and intense rhododendron bloom.

Usually terminal racemose or umbelliferous inflorescences are formed.

The hermaphroditic, mostly five-fold, predominantly radial symmetry to weakly zygomorphic flowers are bell-shaped, tubular, bowl-shaped or trumpet-shaped. The five sepals are fused. Stamens are five to ten (up to 27) present.

The capsule fruits contain numerous seeds. The seeds are usually winged.

Location and care description

In the genus Rhododendron , a rough distinction can be made between the large-flowered, mostly vigorous and taller-growing species and varieties, and the small-flowered, mostly creeping or dwarfed species and varieties. The first are real forest plants that need the umbrella of tall, deep-rooted trees to live and that develop most profusely in the deep forest humus. The dwarf-growing ones, on the other hand, belong to the dwarf wood formation of the high mountains, whose basis of life is a raw humus layer of more or less thickness, with good drainage and high humidity.

The three native species (in Austria and Germany), like all rhododendrons, have very shallow roots (alpine hardly spade-deep), but can also - very rarely - become higher than the average 1.20 m. You absolutely need acidic soils, which you will find in the often thin humus layers on calcareous or dolomite-rich soils (particularly applies to Rhododendron hirsutum ). It is only an apparent contradiction, Rhododendron hirsutum grows in the Limestone Alps and still does not tolerate lime: At such low pH values ​​in the root area, Ca ⁺⁺ ions are from the soil (lime CaCO ₃ or dolomite CaMg (CO ₃ ) ₂ ) hardly present in aqueous solution. Only the tolerance to higher Ca ⁺⁺ concentrations is slightly greater than with other species and varieties.

Rhodothamnus chamaecistus (L.) Rchb is closely related . , the dwarf alpine rose , which occurs only in the Eastern Alps with a distribution area similar to that of Rhododendron hirsutum, for example in the Northern Limestone Alps.

Toxicity

Many rhododendrons are poisonous ; the toxic ingredients, grayanotoxins (including andromedotoxin, grayanotoxin I) from the class of diterpenes , are not only found in leaves, but also in nectar and pollen . There have also been reports of poisoning in humans through excessive consumption of honey from the nectar of Rhododendron ponticum . In the case of severe poisoning, slowed heart activity, weak pulse up to coma and death from respiratory failure can occur. Poisoning has also occurred in grazing animals from eating the leaves.

Types and distribution

There are over a thousand species worldwide, most of which are native to Asia , some in North America , and a few in Europe.

Species of the genus Rhododendron are found everywhere in humid areas of the northern hemisphere and in the southern hemisphere in Southeast Asia and northern Australia . No rhododendrons are native to South America and Africa. The highest biodiversity can be found in the Himalayas in the Uttarakhand area - Nepal and Sikkim , around Yunnan and Sichuan . Other areas with a high diversity of rhododendron species are the mountains of Indochina , as well as Korea , Japan and Taiwan .

Tropical rhododendron species are found from Southeast Asia to Northern Australia, with 55 known species in Borneo and 164 in New Guinea . Relatively few species are native to North America and Europe.

There are ten species in Europe :

• Rust-leaved Alpine rose ( Rhododendron ferrugineum L. ): Alps, Pyrenees, Apennines;
• Lashed Alpine Rose ( Rhododendron hirsutum L. ): Alps;
• Transylvanian Alpine Rose ( Rhododendron kotschyi Simonk. ): Transylvanian Alps, Rhodope Mountains ;
• Lapland alpine rose ( Rhododendron lapponicum (L.) Wahlenb. ): Arctic and subarctic Eurasia;
• Yellow Azalea ( Rhododendron luteum Sweet ): Black Sea, Croatia, Volhynia;
• Pontic rhododendron ( Rhododendron ponticum L. ): Black Sea, Iberian Peninsula;
• Swamp porst ( Rhododendron tomentosum Harmaja ): Northern Europe, Northern Asia and North America

In the Caucasus:

• Caucasian rhododendron ( Rhododendron caucasicum Pall. ),
• Smirnow's Rhododendron ( Rhododendron smirnowii Trautv. ),
• Ungern's Rhododendron ( Rhododendron ungernii Trautv. )

They are completely absent in South America and Africa, but occur in Northern Australia.

In Western and Central Europe, rhododendrons are popular as ornamental shrubs because of their large red, purple or white flower supports . In south-west Ireland there are entire forests of overgrown rhododendrons ( Rhododendron ponticum ), which, as invasive neophytes, pose a threat to biodiversity (e.g. in Sydney National Park ).

Systematics

The name rhododendron , Greek for "rose tree", was used for the oleander until the 17th century and was only transferred to the alpine rose by Carl von Linné .

According to Goetsch et al. In 2005 and Craven 2011, the genus Rhododendron L. with its 600 to 1000 species is divided into:

• Subgenus Rhododendron subg. Rhododendron :
  • Section Rhododendron sect. rhododendron
  • Section Rhododendron sect. Pogonanthum G.Don
  • Section Rhododendron sect. Schistanthe Schltr. : It contains four subsections with about 317 species.
    • Subsection Rhododendron subsect. Discovireya Sleumer (Syn .: Rhododendron sect. Discovireya (Sleumer) Argent ): It contains about 25 species.
    • Subsection Rhododendron subsect. Euvireya H.F. Copel. (Syn .: Rhododendron subg. Vireya C.B.Clarke ), Rhododendron sect. Vireya (CBClarke) HFCopel. , ser. Javanica Rhododendron Sleumer , Rhododendron sect. Hadranthe Schltr. , Rhododendron sect. Hapalanthe Schltr. , Rhododendron sect. Linnaeopsis Schltr. (Syn .: Rhododendron subsect. Linnaeopsis (Schltr.) Sleumer ), Rhododendron ser. Linnaeoidea Sleumer , Rhododendron sect. Zygomorphanthe Schltr. , Rhododendron subsect. Leiovireya H.F. Copel. , Rhododendron subsect. Linear Anthera H.F. Copel. , Rhododendron subsect. Malesia H.F. Copel. , Rhododendron subsect. Solenovireya H.F. Copel. , Rhododendron subsect. Phaeovireya Sleumer , Rhododendron sect. Phaeovireya (Sleumer) Argent , Rhododendron subsect. Astrovireya Sleumer , Rhododendron subsect. Schizovireya Sleumer , Rhododendron subsect. Siphonovireya Sleumer , Rhododendron sect. Siphonovireya (Sleumer) Argent , Rhododendron subsect. Albovireya Sleumer , Rhododendron sect. Albovireya (Sleumer) Argent , Rhododendron ser. Saxifragoidea Sleumer , Rhododendron subsect. Saxifragoidea (Sleumer) Argent , Rhododendron ser. Taxifolia Sleumer , Rhododendron ser. Stenophylla Sleumer , Rhododendron ser. Citrina Sleumer , Rhododendron ser. Buxifolia Sleumer , Rhododendron ser. Dendrolepidone Argent, ALLamb & Phillipps : It contains about 270 species.
    • Subsection Rhododendron subsect. Malayovireya Sleumer (Syn .: Rhododendron sect. Malayovireya (Sleumer) Argent ): It contains about twelve species.
    • Subsection Rhododendron subsect. Pseudovireya (CBClarke) Sleumer (Syn .: Rhododendron subg. Pseudovireya C.B.Clarke , Rhododendron ser. Vaccinioides Hutch. , Rhododendron sect. Pseudovireya (CBClarke) Argent ): It contains about ten species.
• Subgenus Hymenanthes (Blume) K.Koch : It contains two sections with about 224 species:
  • Section Ponticum G.Don : It contains 24 subsections.
  • Section Pentanthera (G.Don) Pojarkova : (Syn .: Rhododendron sect. Pentanthera , Rhododendron subg. Pentanthera (G.Don) Pojarkova ): It contains two subsections.
• Subgenus Azaleastrum Planch. : It contains three sections with over 100 species:
  • Section Rhododendron sect. Azaleastrum Planch. : It contains about five types.
  • Section Rhododendron sect. Sciadorhodion Rehder & Wilson (Syn .: Rhododendron subg. Candidastrum Franch. ): It contains about four species.
• Subgenus Rhododendron subg. Tsutsusi (Sweet) Pojarkova (Syn .: Rhododendron sect. Tsutsusi (Sweet) Pojarkova , Rhododendron sect. Viscidula Matsum. & Nakai , Rhododendron sect. Rhodora (L.) G.Don , Rhododendron subg. Mumeazalea (Sleumer) Mumeazalea (Sleumer) WRPhilipson & ) : It contains about 80 species:
  • Section Rhododendron sect. Tsutsusi (Sweet) Pojarkova
  • Section Rhododendron sect. Brachycalyx Tate ex Sweet (Syn .: Rhododendron subsect. Brachycalyces (Sweet) Spethmann , Rhododendron ser. Dilatata T.Yamaz. , Rhododendron ser. Glangulistyla T.Yamaz. , Rhododendron ser. Nudipes T.Yamaz. , Rhododendron sect. Quinquefolia T. Yamaz. , Rhododendron ser. Reticulata T.Yamaz. , Rhododendron ser. Sciadorhodion T.Yamaz. , Rhododendron sect. Tsusiopsis Sleumer , Rhododendron sect. Verticillata Nakai , Rhododendron ser. Weyrichia, three T.Yamaz. ): Of the approximately eight species in China, six in Japan and one in South Korea.
• Subgenus Therorhodion A.Gray : It contains only two species.
• Subgenus Choniastrum Franch. (Syn. Rhododendron sect. Choniastrum Franch. ): It contains about eleven species.

Before 2005 it was divided into up to twelve sub-categories:

• Subgenus Azaleastrum : around 30 species of evergreen shrubs to small trees.
• Subgenus Candidastrum : with the only species Rhododendron albiflorum Hook.
• Subgenus Hymenanthes : about 270 species of evergreen shrubs or trees, rarely creeping shrubs from which most evergreen garden rhododendrons were grown.
• Subgenus Mumeazalea
• Subgenus Pentanthera : 24 species of deciduous, upright shrubs, rarely trees, including the 15 North American azaleas and the only European one.
• Subgenus Pseudazalea : six species of small to medium-sized, deciduous to semi-evergreen shrubs, rarely evergreen.
• Subgenus Pseudorhodorastrum : ten species of small, evergreen shrubs.
• Subgenus Rhododendron : around 500 species of shrubs, rarely trees, mostly evergreen, rarely deciduous. These include the alpine roses: rust-leaved alpine rose ( Rhododendron ferrugineum ) and lashed alpine rose ( Rhododendron hirsutum )
• Subgenus Rhodorastrum : only two species of small to medium-sized, deciduous to semi-evergreen shrubs.
• Subgenus Therorhodion : three species of deciduous dwarf shrubs .
• Subgenus Tsutsusi : 115 species of deciduous shrubs, sometimes dwarf shrubs, including the Asian azaleas, most of which are native to Japan.
• Subgenus Vireya C.B.Clarke : tropical rhododendron (including 55 species in Borneo, 164 in Guinea)

Characteristic is the number (and shape) of the scales on the leaves, which form the core of the large subdivision into lepidotes (scaled, these are mostly the alpine, small-leaved types like our native ones) and elepidotes (scaly). The gardeners mostly still follow the old classification into azaleas (deciduous, i.e. deciduous). Since it was mainly the British who dealt with rhododendrons through early imports from the USA ( Rhododendron catawbiense ) and later from East Asia, as many people also like the humid climate in England, the English division into "Series" and "Subseries" is usually followed. (for example Davidian in his standard work).

The outdated coarse classification: Lepidote, Elepidote, Vireya (tropical species), Azaleas (can again be divided into summer green and winter green).

In 1998, in the Rhododendron Handbook of the British Royal Horticultural Society (RHS), a revised Sleumer classification (which dates from 1949) was broken down into seven subgenera, which in turn was further divided into sections and subsections. Most of the national rhododendron societies adhere to this.

The variability within a species can be very high. For example, the flower color of Rhododendron ambiguum can vary a lot: the species mostly flowers yellow with green spots, but there are also purple ones. Some American azaleas bloom typically yellow, but also orange to bright red. Information on the flower colors in the literature often ranges from white to pink to crimson, with and without spots, simple and double. Rhododendron schlippenbachii and Rhododendron vaseyi are famous for their pink, but there are also pure white flowers. The shape of the flower can also vary greatly.

Important species and groups of varieties

The small species from the Alps are called alpine roses:

• Alpine roses:
  • Rust-leaved alpine rose ( Rhododendron ferrugineum L. )
  • Lashed Alpine Rose ( Rhododendron hirsutum L. )

Hybrid breeds ( Rhododendron × intermedium ) can occur between the two native Alpine rose species , which can cross and back-cross with the parents. Native shrubs usually survive the winter under snow, which protects them from freezing and drying out.

Many bloom purple to blue: Rhododendron impeditum ; Rhododendron scintillans ; Rhododendron russatum ; Pink and very low: Rhododendron keleticum , Rhododendron radicans . The rather few red-flowered species are famous ( Rhododendron repens ssp. Forrestii , haemaleum , haematodes ; many Repens hybrids from DG Hobbie), there are even black-red flowering ones.

Representatives of the large-flowered species are:

• Rhododendron catawbiense Michx. : one of the oldest imports from North Carolina to Europe and the basis of many breeds (e.g. 'Lee's Dark Purple') and selections ( grandiflorum ); violet with basal spot; very hard and magnificent
• Rhododendron arboreum Sm .: Up to 30 m high, deep red flowers; National plant of Nepal; not hardy
• Rhododendron augustinii Hemsl. : from western China, beautiful blue to blue-violet flowers with spots
• Rhododendron fortunei Lindl. : with very large, fragrant flowers
• Rhododendron sinogrande Balf.f. & WWSm. : with leaves up to 100 cm in length; in Central Europe more in the glass house
• Rhododendron smirnowii Trautv. : very hard in Central Europe
• Rhododendron oreodoxa Franch. and fargesii Franch. : pink, flowering in early April ( oreodoxa )
• Rhododendron strigillosum Franch. : blooms wonderfully red
• Rhododendron sutchuenense Franch. : from Sichuan , very early flowering (end of March) pink; mostly available as a natural hybrid 'Geraldi'
• Rhododendron thomsonii Hook. f. : red bells; Winter protection makes sense
• Rhododendron wardii W.W.Sm. : probably one of the best yellow flowering ones; Flowers also cupped, with or without a red basal spot; Leaves can also be colored blue
• Rhododendron xanthocodon Hutch. : yellow bells; Winter protection required
• Rhododendron metternichii Siebold & Zucc. , makinoi Tagg : from Japan, rather medium-sized, pink to pink / white, very hard
• Rhododendron yakushimanum Nakai : only on the Japanese island that gives it its name; pink bud, white flowers, dark foliage, very hard - the starting point for many breeds (e.g. DG Hobbie, Hachmann )

Representatives of the azaleas are:

• Pot azalea ( Rhododendron simsii Planch. )
• Deciduous, hardy species:
  • Japanese azalea ( Rhododendron japonicum (Blume) CKSchneid. )
  • Western azalea ( Rhododendron occidentale (Torr. & A.Gray) A.Gray )
  • Garden azalea ( Rhododendron molle (Blume) G.Don ), deciduous
  • Rhododendron luteum Sweet (formerly Rhododendron flavum G.Don ; formerly Azalea pontica ), the only European azalea
  • Flame azalea ( Rhododendron calendulaceum (Michaux) Torrey ) from the Appalachian Mountains / USA

and the

• Bog porst ( Rhododendron tomentosum Harmaja ), originally known as Ledum palustre L.

Rhododendron varieties

There are many rhododendron varieties in many breeding directions.

→ Main article : Rhododendron varieties

Parks with rhododendrons

There are many parks and botanical gardens with many rhododendrons.

→ Main article : List of rhododendron parks

Diseases

Rhododendron leaf hoppers mating

Incorrect site conditions can lead to diseases in rhododendrons. Different types of disease are: fungal attack, leaves turning brown, buds drying up. Pest infestation, for example by weevils , also leads to impairment of the plant.

Red, gelatinous growths, so-called alpine rose apples, are striking in the two types of alpine rose . Another disease is bud rot . It can be transmitted by the rhododendron leafhopper. This cicada slits open the young buds to lay their eggs there. The fungus Pycnostysanus azaleae can then more easily penetrate the plant through these slots and multiply.

The rhododendron lattice bug ( Stephanitis rhododendri ) was introduced from Japan . The bug sucks on the midrib, causing the leaves to turn brown and fall off. Hibernate the eggs laid in July. The offspring hatch in May.

swell

literature

• LA Craven, F. Danet, JF Veldkamp, ​​Loretta A. Goetsch, BD Hall: Vireya Rhododendrons: their monophyly and classification (Ericaceae, Rhododendron section Schistanthe). In: Blumea. Volume 56, 2011, pp. 153-158, PDF file. (Section systematics)
• Loretta A. Goetsch, Andrew J. Eckert, Benjamin D. Hall: The molecular systematics of Rhododendron (Ericaceae): A phylogeny based upon RPB2 gene sequences. In: Systematic Botany. Volume 30, 2005, pp. 616-626, doi : 10.1600 / 0363644054782170 . (Section systematics)
• Fang Mingyuan (方明渊), Fang Ruizheng (方 瑞 征 Fang Rhui-cheng), He Mingyou (何明友), Hu Linzhen (胡琳贞 Hu Ling-cheng), Yang Hanbi (杨汉 碧), David F. Chamberlain: Rhododendron. In: Wu Zheng-yi, Peter H. Raven, Deyuan Hong (Eds.): Flora of China . Volume 14: Apiaceae through Ericaceae . Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 2005, ISBN 1-930723-41-5 , pp. 260 (English, online ). (Section systematics)
• Eberhard Teuscher, Ulrike Lindequist: Biogenic poisons. Biology, chemistry, pharmacology, toxicology. 3rd revised and expanded edition. Wissenschaftliche Verlagsgesellschaft, Stuttgart 2010, ISBN 978-3-8047-2438-9 , pp. 177-180.
• Günter Hoppe: Rhododendron - the rose tree. Not long at home in gardens and parks . In: Men from Morgenstern , Heimatbund an Elbe and Weser estuary e. V. (Ed.): Niederdeutsches Heimatblatt . No. 810 . Nordsee-Zeitung GmbH, Bremerhaven June 2017, p. 1–2 ( digitized version [PDF; 2.4 MB ; accessed on July 15, 2019]).

Supplementary literature

to the types:

• J. Cullen: Hardy Rhododendron Species: A Guide to Identification. Timber Press Inc., Portland 2005.
• J. Cullen: Revision of Rhododendron I. Subgenus Rhododendron, Section Rhododendron and Pogonanthum. In: Notes from the Royal Botanic Garden Edinburgh. Volume 39, No. 1, 1980.
• G. Argent, J. Bond, D. Chamberlain, P. Cox, A. Hardy: The Rhododendron Handbook. RHS, London 1988.
• G. Argent: Rhododendrons of Subgenus Vireya. Royal Horticultural Society with the Royal Botanic Garden Edinburgh 2008.
• D. Chamberlain, R. Hyam, G. Argent, G. Fairweather, KS Walter: The Genus Rhododendron: Its Classification and Synonymy. Royal Botanic Garden, Edinburgh 1996.
• PA Cox, KNE Cox: Encyclopedia of Rhododendron Species. Glendoick Publishing, Perth 1997.
• PA Cox: The Smaller Rhododendrons. Timber Press Inc., Portland 1985.
• PA Cox: The Larger Species of Rhododendron. Batsford Ltd. 1979.
• HH Davidian: The Rhododendron Species. Volume I-IV. Batsford Ltd. 1982-1995.
• E. Moser: Rhododendrons. Wild species and hybrids. Erhard Neumann, Stuttgart 1997.
• LC Towe: American Azaleas. Timber Press Inc., Portland 2004.

to the varieties:

• Bundessortenamt: Descriptive list of varieties, Topfazalee , 2nd edition. Landbuch-Verlag 2000.
• KNE Cox: Rhododendrons & Azaleas. The Crowood Press Ltd., Ramsbury 2005.
• A. De Raedt & S. De Groote: De Harde Gentse. Gavere 2000.
• F. Galle: Azaleas. Timber Press Inc., Portland 1987.
• W. Schmalscheidt: Rhododendron breeding in Germany. 2nd Edition. Self-published, Oldenburg 2002.
• W. Schmalscheidt: Rhododendron and azalea breeding in Germany. , 2nd Edition. Garden picture by Heinz Hansmann, Rinteln 1991.
• W. Schmalscheidt: Handbook of the Knap Hill Azaleas. Garden picture by Heinz Hansmann, Rinteln 2000.
• The Royal Horticultural Society: The International Rhododendron Register and Checklist. 2nd. Ed. The Royal Horticultural Society, London 2004.
• DM Van Gelderen, JRP Van Hoey Smith: Rhododendron Atlas. Eugen Ulmer, Stuttgart 1991.

for design:

• U. Borstell, J. Westhoff: Azaleas and Rhododendrons - Simply fascinating. DVA, Munich 2014.

Web links

Commons : Rhododendron  - Collection of Images

Wiktionary: Rhododendron  - explanations of meanings, word origins, synonyms, translations

• German Rhododendron Society eV
• German gene bank Rhododendron
• Rhododendron Cultures
• Compilation of popular garden varieties

Individual evidence

1. ↑ https://www.duden.de/rechtschreibung/Rhododendron
2. ↑ Der, die or das Rhododendron ?: Foundation Bremen Rhododendron Park. Retrieved May 19, 2017 . 
3. ↑ KK Singh, LK Rai and B. Gurung (2009): Conservation of Rhododendrons in Sikkim Himalaya: An Overview. World Journal of Agricultural Sciences 5 (3): 284-296.
4. ↑ LA Craven, F. Danet, JF Veldkamp, ​​LA Goetsch, BD Hall (2011): Vireya Rhododendrons: their monophyly and classification (Ericaceae, Rhododendron section Schistanthe). Blumea 56: 153-158. doi: 10.3767 / 000651911X590805
5. ↑ Peter Hanelt: Ericales. In: Franz Fukarek (ed.): Urania plant kingdom. Volume 4: Flower Plants 2, Urania, Berlin 2000, ISBN 3-332-01170-7 , pp. 106-107.
6. ↑ About Rhododendrons. by Rhododendron Species Foundation .
7. ↑ George Argent: Rhododendrons of subgenus Vireya . Royal Horticultural Society, London 2006, ISBN 1-902896-61-0 .
8. ↑ ^{a b} L. A. Craven, F. Danet, JF Veldkamp, ​​Loretta A. Goetsch, BD Hall: Vireya Rhododendrons: their monophyly and classification (Ericaceae, Rhododendron section Schistanthe). In: Blumea. Volume 56, 2011, pp. 153-158 (PDF file).
9. ^ BD Hall, LA Craven, Loretta A. Goetsch: The taxonomy of subsection Pseudovireya - Two distinctly different taxa within subsection Pseudovireya and their relation to the rooting of section Vireya within subgenus Rhododendron. In: Rhododendron Species. Volume 1, No. 72, 2006, pp. 91-97.
10. ^ David F. Chamberlain, SJ Rae: A revision of Rhododendron IV subgenus Tsutsusi. In: Edinburgh Journal of Botany. Volume 47, 1990, pp. 89-200, DOI: 10.1017 / S096042860000319X .
11. ↑ Jin Xiao-Feng, Ding Bing-Yang, Zhang Yue-Jiao, Hong De-Yuan: A Taxonomic Revision Of Rhododendron subg. Tsutsusi sect. Brachycalyx (Ericaceae). In: Annals of the Missouri Botanical Garden. Volume 97, No. 2, 2010, pp. 163-190, doi : 10.3417 / 2007139 .

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !