Hoya

Hoya lanceolata subsp. bella

Wax flowers ( Hoya ), also called porcelain flower, is a genus in the subfamily of the milkweed family ( Asclepiadoideae ) within the family of the dogbane family ( Apocynaceae ). A number of species and their varieties are used as ornamental plants.

5.1 Notes and references

Description

Vegetative characteristics

Hoya species grow mostly epiphytic, lithophytic and rarely terrestrial. There are perennial herbaceous or slightly woody plants, vines or sometimes subshrubs. The shoot axes are hanging up twining, climbing by adventitious roots or self upright. The Stems are hairy at most sparsely fluffy; aged are often significantly lenticels visible. They contain white latex. The roots are fibrous, and the shoot axes form sprossbürtige roots. They are mostly evergreen; Hoya spartioides is deciduous.

The leaves are always arranged against constantly with one exception ( Hoya imbricata ). The leaves are divided into petiole and leaf blade. The simple, flat leaf blade is dorsiventral, fleshy, leathery, succulent, membranous, papery or with wax layer, one or two colors and entire. Often the leaves are silver spots and at the base of a extraflorales nectary. In some species the leaves are hairy. The Blattnervatur is usually almost parallel, rarely pinnately; usually without lateral nerves.

Inflorescences and flowers

In the internodes are single, in a more or less long Blütenstandsschäften that often take over tasks photosynthesis, or without Blütenstandsschäfte doldige simple or racemose, or branched scheindoldige inflorescences, which often contain many flowers.

The flowers smell sweet to hard or are odorless. The stalked, hermaphroditic, flowers are radial symmetry fünfzählig double perianth ( perianth ). The five sepals are fused. The five petals are fused to one-half to nearly all ( Hoya inflata, Hoya manipurensis ) Length stern, wheel -, bell -, urns ( Hoya manipurensis ) or salverform and may be fleshy and / or have a wax coating. The colors of the petals range from white to cream to yellow and brown and pink to reddish. The outer side of the petals is usually glabrous; Hoya manipurensis trichomes are present. The inside of the petals is sometimes covered with short erect; Hoya inflata is papillose. It's just a circle with five fertile stamens same present. The stamens have appendages and are mutually partially fused into a staminal tube; the free part of five outspread, fleshy corona lobes and the deformed part form the corona. The colors of the corona range from white to ivory to yellow and green or pink. In Hoya multiflora just spurs are formed. The anthers form a Gynostegium with the scars. The upright pole lines end in a sterile field. The two carpels are a top permanent, zweifächerigen ovary fused with 30 to 50 ovules. The two pens are fused at the top and terminating in a common conical to ovoid scar. They have, like all other genera of the subfamily of Asclepiadoideae, a complicated pollination mechanism (terminal case flowers).

Fruit and seeds

The mostly single (not pairs present as in many genera of this subfamily ) hanging follicles are smooth, relatively thin and elongated, pencil -shaped, spindle-shaped (for example, Hoya coriacea, Hoya griffithii ) or ellipsoidal ( Hoya coronaria, and with it the closely related species), always without edges, usually 4 to 10 ( rare example Hoya longifolia to 30) inches long, have a thin, often woody or thick ( at Hoya coronaria and their closely related species ) pericarp and contain many seeds. As diasporas the egg-shaped to oblong, 1-5 mm long and 1 to 2.5 mm wide dismissed seeds, which is a wing and a 2 to 3 cm long hair tufts as a flight organ only at the end; the spread is done so by wind.

Chromosome numbers

The previously investigated species have chromosome numbers of 2n = 22

Occurrence

The genus Hoya has a wide natural range in Asia, Australia and Oceania. It extends from the Indian subcontinent to the Fiji Islands and Samoa. They come from southern China ( 40 species ) to Vietnam and Indonesia over Malaysia, New Guinea, the Philippines ( 68 species ) to Japan and from northern Australia to New Caledonia before ( 32 species ) via Myanmar, Nepal, Thailand. They thrive at altitudes of about 2500 meters. The habitats are in Southeast Asia is always wet, tropical rain forest, in northern Australia and in the northeastern Thailand, the dry forest and cloud forest in the mountains. They thrive for example, in coastal areas, a variety of forest types, often near streams, on rocks and on trees.

By logging and the associated Verinselung of habitats, many species are threatened in their natural occurrence.

Use

Some Hoya varieties are cultivated as houseplants. Hoya carnosa is probably the most famous house plant of this genus. Many species have hanging up twining stem axis. An upright growing species is as Hoya multiflora. Some types of varieties were with white- colored ( variegated ) selected leaves. Examples: Hoya carnosa cv. ' Tricolor' and Hoya bella cv. ' Tricolor' and Hoya macrophylla cv. 'Variegata'.

The Hoya species and varieties are propagated by cuttings or rarely with seeds.

System

The genus name Hoya was first published in 1810 by Robert Brown in Prodromus Novae Florae Hollandiae, p 459. Is the type species Hoya carnosa (L.) R.Br., which was first published as Asclepias carnosa L.. The botanical genus name honors the English gardener Hoya Thomas Hoy. For valid genus name Hoya R.Br. There are a variety of synonyms. Absolmsia Kuntze, Astrostemma Benth, non Asterostemma Decne, Acanthostemma ( flower ) flower, Antiostelma ( Tsiang & PTLi ) PTLi, Cent rust Emma Decne, Cyrtoceras Bennet, Cystidianthus Hassk, Madangia PIForst. .. . DJLiddle & IMLiddle, Micholitzia NEBr. , Otostemma flower, Physostelma Wight, Plocostemma flower, Pterostelma Wight, Schollia Jacq., Sperlingia Vahl, Triplosperma G.Don .. the genus Hoya belongs to the tribe Marsdenieae in the subfamily Asclepiadoideae within the family of the Apocynaceae.

There about 400 Hoya species names have been published, of which only about (70 to ) 300 species are valid. The genus Hoya has been processed several times in the past. There has been no monograph of the genus Hoya. In recent years, the Stockholm University has been at the Institute for " Phanerogamicbotany " examined using DNA analyzes, the phylogeny of the genus.

The following list represents only a part of all known Hoya species is:

Hoya acuta
Hoya affinis
Hoya albiflora
Hoya aldrichii
Hoya anulata
Hoya archboldiana
Hoya arnottiana
Hoya aurantiaca Kloppenburg, Siar & Cajano
Hoya australis R.Br. ex J.Traill
Hoya baishaensis S.Y.He & P.T.Li
Hoya bawanglingensis S.Y.He & P.T.Li
Hoya benguetensis
Hoya bhutanica
Hoya bilobata
Hoya bordenii
Hoya brevialata
Hoya burtoniae
Hoya callistophylla
Hoya calycina
Hoya campanulata
Hoya camphorifolia Warblers.
Hoya carnosa ( L. f ) R.Br. ( Syn: . Hoya motoskei Teijsm & Binn. )
Hoya caudata
Hoya cembra
Hoya chinghungensis ( Tsiang & PTLi ) MGGilbert & PTLi & WDStevens
Hoya chlorantha
Hoya chuniana
Hoya ciliata
Hoya cinnamomifolia Hook.
Hoya citrina
Hoya clemensiorum
Hoya collina
Hoya cominsii
Hoya compacta
Hoya commutata M.G.Gilbert & P.T.Li
Hoya cordata P.T.Li & S.Z.Huang
Hoya coriacea Blume
Hoya coronaria flower
Hoya crassicaulis
Hoya cumingiana
Hoya curtisii
Hoya darwinii
Hoya dasyantha Tsiang
Hoya davidcummingii
Hoya dennisii
Hoya densifolia
Hoya deykei
Hoya dimorpha
Hoya diptera
Hoya dischorensis
Hoya diversifolia Blume
Hoya dolicosparte
Hoya elliptica
Hoya endauensis
Hoya engleriana
Hoya erythrina
Hoya erythrostemma
Hoya eitapensis
Hoya excavata
Hoya flagelleta
Hoya flavescens
Hoya flavida
Hoya fraterna flower
Hoya fungii Merrill
Hoya fusca Wallich
Hoya glabra
Hoya globulosa Hook.f.

Hoya gracilis
Hoya greenii
Hoya griffithii Hook.f.
Hoya guppyi
Hoya halophila
Hoya heuschkeliana
Hoya hypolasia
Hoya imbricata Decne.
Hoya imperialis Lindl.
Hoya inconspicua
Hoya incrassata
Hoya incurvula
Hoya inflata ( PIForst., DJLiddle & IMLiddle ) L.Wanntorp
Hoya ischnopus
Hoya juanngoiana
Hoya kanyakumariana
Hoya kenejiana
Hoya kentiana
Hoya kerrii Craib
Hoya keysii F.M.Bailey
Hoya kuhlii ( flower) Coord
Hoya lacunosa Blume
Hoya lanceolata Wall. ex D.Don (including H. bella )
Hoya landgrantensis Kloppenburg, Siar & Cajano
Hoya lasiantha Korth. ex Blume
Hoya lasiogynostegia P.T.Li
Hoya latifolia
Hoya lauterbachii
Hoya liangii Tsiang
Hoya lii C.M.Burton
Hoya limoniaca
Hoya linearis Wallich ex D.Don
Hoya lipoensis P.T.Li & Z.R.Xu
Hoya litoralis
Hoya lobbii
Hoya loheri
Hoya longifolia Wall. ex Wight
Hoya lucardenasiana Kloppenburg, Siar & Cajano
Hoya lyi H.Léveillé
Hoya macgillivrayi F.M.Bailey
Hoya macrophylla
Hoya magnifica
Hoya manipurensis Deb.
Hoya mekongensis M.G.Gilbert & P.T.Li
Hoya mega laster
Hoya Meliflua
Hoya mengtzeensis Tsiang & P.T.Li
Hoya merrillii
Hoya micrantha
Hoya microphylla
Hoya mindorensis
Hoya mitrata
Hoya montana
Hoya multiflora Blume
Hoya naumanii
Hoya nawbawenensis
Hoya neocaldonica
Hoya neoebudica
Hoya nervosa Tsiang & P.T.Li
Hoya nummularioides
Hoya obovata Decne.
Hoya obscura
Hoya odetteae
Hoya onychoides

Hoya oreogena
Hoya ovalifolia Wight & Arnott
Hoya pachyclada
Hoya padangensis
Hoya palawanica
Hoya pallilimba
Hoya pandurata Tsiang
Hoya parasitica
Hoya parviflora
Hoya patella
Hoya pauciflora
Hoya paziae
Hoya pentaphlebia
Hoya picta
Hoya pimenteliana
Hoya plicata
Hoya polystachya
Hoya polyneura Hook. f
Hoya pottsii Decne. ( Syn: Hoya angustifolia J.Traill )
Hoya pubicalyx
Hoya pulchella
Hoya purpurea
Hoya purpureofusca Hook.
Hoya pusilla Rintz
Hoya radicalis Tsiang & P.T.Li
Hoya retusa
Hoya revolubilis Tsiang & P.T.Li
Hoya revoluta
Hoya ridleyi King & Gamble
Hoya rigida
Hoya ruscifolia
Hoya salweenica Tsiang & P.T.Li
Hoya samoensis
Hoya schneei
Hoya serpens
Hoya shepherdii
Hoya siamica Craib
Hoya siariae Kloppenburg
Hoya sigillatis
Hoya sylvatica Tsiang & P.T.Li
Hoya sipitangensis
Hoya solaniflora Schltr.
Hoya soligamiana Kloppenburg, Siar & Cajano
Hoya spartioides ( Benth. ) Kloppenb.
Hoya subcalva
Hoya subglabra
Hoya subquintuplinervis
Hoya teretifolia
Hoya thailandica
Hoya thomsonii Hook. f
Variegata Hoya
Hoya verticillata ( Vahl ) G.Don
Hoya villosa Costantin
Hoya vitellinoides
Hoya vitiensis
Hoya wallichii
Hoya walliniana
Hoya wayetii
Hoya waymaniae
Hoya wightii
Hoya wilbergiae Kloppenburg

Swell

Sigrid songs Schumann & Ulrich Meve: The Genera of Asclepiadoideae, Secamonoideae and Periplocoideae ( Apocynaceae ), 2006: The genus Hoya - Online at INTKEY databases of the DELTA system. (Section Description, occurrence and systematics)
Focke Albers & Ulrich Meve (ed.): Sukkulentenlexikon Volume 3 Asclepiadaceae ( milkweed family). Eugen Ulmer Verlag, Stuttgart 2002, ISBN 3-8001-3982-0.
Uwe Scharf: The genus Hoya ( Apocynaceae ) - a portrait. In: cacti and other succulents. Volume 57, No. 1, 2006, pp. 1-10
B. Richardson: Hoya in the Western Australian Flora:. Online, 2008 (Section Description )
Bingtao Li, Michael G. Gilbert & Douglas W. Stevens: Asclepiadaceae in the Flora of China, Volume 16, 1995, p 228: Hoya - Online.
R. Omlor: Generic revision of the Marsdenieae ( Asclepiadaceae ), PhD thesis at the University of Kaiserslautern, 1998.
Livia Wanntorp & PI Forster: Phylogenetic relationships in between Hoya and the monotypic genera Madangia, Absolmsia, and Micholitzia ( Apocynaceae, Marsdenieae ): insights from flower morphology, in Annals of the Missouri Botanical Garden, 94, 2007, pp. 36-55. .
Livia Wanntorp, A. Kocyan, R. van Donkelaar & SS Renner: Towards a monophyletic Hoya ( Marsdenieae, Apocynaceae ): Inferences from the chloroplast trnL region and the rbcL - atpB spacer, In: . Systematic Botany, 31, 2006, pp. 586-596.
Livia Wanntorp: Phylogenetic systematics of Hoya ( Apocynaceae ), In: . Blumea, 54, 2009, pp. 228-232
Livia Wanntorp: Systematics of the genus Hoya - Challenges and reward, In: Avonia, 27 (3 ), 2009, pp. 104-112. .

Gentianales Lithophyte Ovary (botany) Thomas Hoy (botanist)

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