Hoya
Encyclopedia
Hoya is a genus
of 200-300 species of tropical plants in the family
Apocynaceae
(Dogbane family), fomerly considered to be in the Asclepiadaceae
(milkweed family). Most are native to Asia
including India
, China
, Thailand, Malaysia, and Indonesia
, There is a great diversity of species in the Philippines
, and species in Polynesia
, New Guinea
, and Australia
.
Common names for this genus are waxplant, waxvine, waxflower or simply hoya. This genus was named by botanist Robert Brown
, in honour of his friend, botanist Thomas Hoy.
perennial creepers or vine
s or rarely, shrub
s. They often grow epiphyticaly on trees; some grow terrestrially, or occasionally in rocky areas. They climb by twining, and with the employment of adventitious roots. Larger species grow 1-18 m (3 to 60 ft.), or more, with suitable support in trees. They have simple entire leaves
, arranged in an opposite pattern, that are typically succulent. Leaves may exhibit a variety of forms, and may be smooth, felted or hairy; veination may be prominant or not, and many species have leaf surfaces flecked with irregular small silvery spots.
The flower
s appear in axillary
umbellate
clusters at the tip of a peduncles
. Hoya peduncles are commonly referred to as spurs. In most species these spurs are perennial and are rarely shed. Each flowering cycle increases the length of the spur, and in the larger species can eventually reach 27 cm (11 in.) or more. Flowers vary in size from 3mm (Hoya bilobata Schltr.) to over 95 mm (in H. lauterbachii K. Schuman) in diameter. Flower form is typically star-shaped, with five thick, waxy, triangular petals, topped with another star-shaped structure, the corona. Colours on most species range from white to pink; there are species that exhibit yellow to orange, dark reds to near-black, and there are green flowers. Many are sweetly scented. and most produce abundant nectar.
Pollenators include moths, flies, and ants. Pollenation is poorly understood, but plants left outdoors in temperate regions do sometimes produce seed, indicating pollenation by local insects.
Seeds are borne in twin pods, actually follicles, are generally light, and are dispersed by the wind by means of a small tuft of silky fluff. Germination is rapid, but viability is not long.
At least some species exhibit Crassulacean Acid Metabolism
(CAM), including H. carnosa.
Several species exhibit adaptations for mutualism
with ants by providing modified leaves for domatia
("homes"), much as in the related genus Dischidia
; H. imbricata has leaves that form a concave cup over the tree trunk it climbs up to shelter ants, and H. darwinii has arrangements of bullate leaves on its stems to form shelters.
s in temperate areas (especially H. carnosa), grown for their attractive foliage and strongly scented flower
s. Numerous cultivar
s have been selected for different leaf forms or flower colours. Hoyas grow well indoors, preferring bright light, but will tolerate fairly low light levels, although they may not flower without bright light. Hoyas commonly sold in nurseries as houseplants include cultivars of H. carnosa (Krimson Queen, Hindu Rope − compacta), H. pubicalyx (often mislabeled as H. carnosa or H. pururea-fusca), and H. kerrii. Hoyas are easy to propagate, and are commonly sold as cuttings, either rooted or unrooted, or as a potted plant.
Hoya carnosa has been shown in recent studies at the University of Georgia to be an excellent remover of pollutants in the indoor environment.
Various cultures have used Hoyas medicinally, especially Polynesian cultures. Some are toxic to livestock and sheep poisonings in Australia are reported.
Hoya flowers are all are shaped like five pointed stars. Some of the species' petals reflex so far the the flowers appear to be round or ball-like. They grow in umbel
s, or in some species singly. Umbels can reach impressive proportions in some species, and many species have individual flowers well over three inches in diameter (H. imperialis Lindl., H. lauterbachii K. Schuman). H. coriacea Blume has been known to have as many as 70 in an inflorescence, each individual measuring nearly 2 cm in diameter with the umbels over 30 cm in breadth. The single-flowered Hoya pauciflora Wight makes up for its paucity by its flower size of nearly an inch and a half in diameter produced at any time of year. Textures of flower surfaces may be glabrous and shiny, to matte, to finely haired, and some being quite hairy. One of the two clones of Hoya mindorensis Schltr., from the Philippines, comes very close to being a true red. Blue, purples, and violets do not appear to be represented in the genus Hoya.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of 200-300 species of tropical plants in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Apocynaceae
Apocynaceae
The Apocynaceae or dogbane family is a family of flowering plants that includes trees, shrubs, herbs, and lianas.Many species are tall trees found in tropical rainforests, and most are from the tropics and subtropics, but some grow in tropical dry, xeric environments. There are also perennial herbs...
(Dogbane family), fomerly considered to be in the Asclepiadaceae
Asclepiadaceae
According to APG II, the Asclepiadaceae is a former plant family now treated as a subfamily in the Apocynaceae...
(milkweed family). Most are native to Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
including India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, Thailand, Malaysia, and Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, There is a great diversity of species in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, and species in Polynesia
Polynesia
Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...
, New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
, and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Common names for this genus are waxplant, waxvine, waxflower or simply hoya. This genus was named by botanist Robert Brown
Robert Brown (botanist)
Robert Brown was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope...
, in honour of his friend, botanist Thomas Hoy.
Summary
Hoyas are evergreenEvergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
perennial creepers or vine
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
s or rarely, shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s. They often grow epiphyticaly on trees; some grow terrestrially, or occasionally in rocky areas. They climb by twining, and with the employment of adventitious roots. Larger species grow 1-18 m (3 to 60 ft.), or more, with suitable support in trees. They have simple entire leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
, arranged in an opposite pattern, that are typically succulent. Leaves may exhibit a variety of forms, and may be smooth, felted or hairy; veination may be prominant or not, and many species have leaf surfaces flecked with irregular small silvery spots.
The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s appear in axillary
Axillary
Axillary means "related to the axilla "."Axillary" may refer to:* Axillary artery* Axillary vein* Axillary nerve* Axillary bud...
umbellate
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
clusters at the tip of a peduncles
Peduncle (botany)
In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...
. Hoya peduncles are commonly referred to as spurs. In most species these spurs are perennial and are rarely shed. Each flowering cycle increases the length of the spur, and in the larger species can eventually reach 27 cm (11 in.) or more. Flowers vary in size from 3mm (Hoya bilobata Schltr.) to over 95 mm (in H. lauterbachii K. Schuman) in diameter. Flower form is typically star-shaped, with five thick, waxy, triangular petals, topped with another star-shaped structure, the corona. Colours on most species range from white to pink; there are species that exhibit yellow to orange, dark reds to near-black, and there are green flowers. Many are sweetly scented. and most produce abundant nectar.
Pollenators include moths, flies, and ants. Pollenation is poorly understood, but plants left outdoors in temperate regions do sometimes produce seed, indicating pollenation by local insects.
Seeds are borne in twin pods, actually follicles, are generally light, and are dispersed by the wind by means of a small tuft of silky fluff. Germination is rapid, but viability is not long.
At least some species exhibit Crassulacean Acid Metabolism
Crassulacean acid metabolism
Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions. The stomata in the leaves remain shut during the day to reduce evapotranspiration, but open at night to collect carbon dioxide...
(CAM), including H. carnosa.
Several species exhibit adaptations for mutualism
Mutualism
Mutualism is the way two organisms of different species biologically interact in a relationship in which each individual derives a fitness benefit . Similar interactions within a species are known as co-operation...
with ants by providing modified leaves for domatia
Domatia
Domatia are tiny chambers produced by plants that house arthropods.Domatia differ from galls in that they are produced by the plant rather than being induced by their inhabitants...
("homes"), much as in the related genus Dischidia
Dischidia
Dischidia is a genus of plants in the Milkweed family, Asclepiadaceae. It comprises about 80 known species which all grow as epiphytes and are native to tropical areas of China, India and most areas of Indo-China. Dischidia are closely aligned with the sister genus Hoya...
; H. imbricata has leaves that form a concave cup over the tree trunk it climbs up to shelter ants, and H. darwinii has arrangements of bullate leaves on its stems to form shelters.
Cultivation and uses
Many species of Hoya are popular houseplantHouseplant
A houseplant is a plant that is grown indoors in places such as residences and offices. Houseplants are commonly grown for decorative purposes, positive psychological effects, or health reasons such as indoor air purification...
s in temperate areas (especially H. carnosa), grown for their attractive foliage and strongly scented flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s. Numerous cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s have been selected for different leaf forms or flower colours. Hoyas grow well indoors, preferring bright light, but will tolerate fairly low light levels, although they may not flower without bright light. Hoyas commonly sold in nurseries as houseplants include cultivars of H. carnosa (Krimson Queen, Hindu Rope − compacta), H. pubicalyx (often mislabeled as H. carnosa or H. pururea-fusca), and H. kerrii. Hoyas are easy to propagate, and are commonly sold as cuttings, either rooted or unrooted, or as a potted plant.
Hoya carnosa has been shown in recent studies at the University of Georgia to be an excellent remover of pollutants in the indoor environment.
Various cultures have used Hoyas medicinally, especially Polynesian cultures. Some are toxic to livestock and sheep poisonings in Australia are reported.
Leaves
Hoya leaves vary in size, texture, color and venation. In size, leaves range from as small as 5 mm in length and 2 to 4 mm in width (Hoya engleriana Hosseus) to as large as 25 cm. by 35 cm. (Hoya latifolia G. Don). Hoya coriacea Blume, has been reported have leaves as long as two feet in length. There are hoyas with almost perfectly round leaves and others with linear leaves (Hoya linearis Wall. ex. D. Don and Hoya teretifolia Griff. ex Hook. f.). One popular species, Hoya shepherdii Short ex Hook. has leaves that resemble string beans hanging in bunches from their stalks. Hoya linearis Wall. ex D. Don is covered with fine downy hair and resembles masses of Spanish Moss (Tillandsia useneoides) hanging from trees in its native habitat. Some Hoya leaves are smooth and shiny; some are covered with hairs. Some Hoya leaves appear to be veinless while others have very conspicuous veins of a lighter or darker colour than the rest of the leaves as in H. cinnomomifolia. Some have leaves that are mottled with speckles of silvery white (Hoya carnosa R. Br., Hoya pubicalyx). Some hoyas have leaves that are thin and translucent (Hoya coriacea Blume); some are so thick and succulent that they look more like crassulas than hoyas (Hoya australis ssp. rupicola, oramicola and saniae from Australia and Hoya pachyclada from Thailand). One of the most succulent, Hoya kerrii Craib, has valentine heart shaped leaves, with notches at the apexes of the leaves instead of at the bases.Flowers
Umbel
An umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....
s, or in some species singly. Umbels can reach impressive proportions in some species, and many species have individual flowers well over three inches in diameter (H. imperialis Lindl., H. lauterbachii K. Schuman). H. coriacea Blume has been known to have as many as 70 in an inflorescence, each individual measuring nearly 2 cm in diameter with the umbels over 30 cm in breadth. The single-flowered Hoya pauciflora Wight makes up for its paucity by its flower size of nearly an inch and a half in diameter produced at any time of year. Textures of flower surfaces may be glabrous and shiny, to matte, to finely haired, and some being quite hairy. One of the two clones of Hoya mindorensis Schltr., from the Philippines, comes very close to being a true red. Blue, purples, and violets do not appear to be represented in the genus Hoya.
Selected species
- Hoya acicularis
- Hoya acuminata
- Hoya acuta
- Hoya aeschynanthoides
- Hoya affinis
- Hoya africana
- Hoya alagensis (Philippines)
- Hoya alata
- Hoya alba
- Hoya albens
- Hoya albiflora
- Hoya aldrichiiHoya aldrichiiHoya aldrichii , commonly known as the Christmas Island Waxvine is a species of flowering plant in the Apocynaceae or dogbane family. It is a vine that is endemic to Christmas Island, an Australian territory in the north-eastern Indian Ocean, where it is a common epiphyte in the shrublands of the...
(Christmas Island) - Hoya alexicaca
- Hoya amboinensis
- Hoya ambon
- Hoya amoena
- Hoya andalensis
- Hoya angustifolia (Philippines)
- Hoya angustisepala
- Hoya anncajanoae (Philippines)
- Hoya anulata
- Hoya apiculata
- Hoya apoda
- Hoya archboldiana
- Hoya ariadna
- Hoya arnottiana
- Hoya attenuata
- Hoya augustifolia
- Hoya aurantiaca (Philippines)
- Hoya australisHoya australisHoya australis, commonly known as the Waxvine or Common waxflower, is one of the species in the genus Hoya. It is a vine found on rainforest margins and rocky areas, and occurs in eastern and northern Australia, from the Northern Territory though coastal Queensland from Cape York to northern New...
- Australian Waxflower (Australia, Papua New Guinea) - Hoya australis ssp. australis
- Hoya australis ssp. keysii
- Hoya australis ssp. naumanii
- Hoya australis ssp. oramicola
- Hoya australis ssp. rupicola
- Hoya australis ssp. sana
- Hoya australis ssp. tenuipes
- Hoya bandensis
- Hoya bella - Beautiful Hoya
- Hoya benguetensis (Philippines)
- Hoya benitotanii (Philippines)
- Hoya benvergarai (Philippines)
- Hoya betchei
- Hoya bhutanica
- Hoya bicknellii (Philippines)
- Hoya bilobata (Philippines)
- Hoya blashernaezii (Philippines)
- Hoya bordenii (Philippines)
- Hoya brevialata
- Hoya buotii (Philippines)
- Hoya burtoniae (Philippines)
- Hoya cagayanensis (Philippines)
- Hoya callistophylla
- Hoya calycina
- Hoya calycina ssp. calycina
- Hoya campanulata
- Hoya camphorifolia (Philippines)
- Hoya cardiophylla - Heart Leaf Hoya (Philippines)
- Hoya carnosa - Porcelain Flower, Waxplant (China, Souheast Asia, Malesia)
- Hoya caudata
- Hoya cembra - syn. Hoya odorata
- Hoya chlorantha
- Hoya chuniana
- Hoya chunii
- Hoya ciliata - syn. Eriostemma ciliata (Philippines)
- Hoya cinnamomifoliaHoya cinnamomifoliaHoya cinnamomifolia is a vine that comes from the island of Java. It is one of the larger members of the Hoya genus with typically one leaf per node. Each leaf is large, dark green, and has lighter colored vains that run parallel to the leaf. The leaves can get as big as 15cm by 6cm...
- Hoya citrina
- Hoya clandestina
- Hoya clemensii
- Hoya clemensiorum
- Hoya collina
- Hoya cominsii
- Hoya compacta
- Hoya conchoi
- Hoya coriacea - syn. Hoya angustisepala (Philippines)
- Hoya coronaria
- Hoya crassicaulis (Philippines)
- Hoya crassipes
- Hoya cumingiana (Philippines)
- Hoya curtisii (Philippines and Thailand)
- Hoya cystiantha
- Hoya dasyantha
- Hoya darwinii - Ant Hoya (Philippines)
- Hoya davidcummingii (Philippines)
- Hoya dennisii
- Hoya densifolia (Philippines)
- Hoya deykei
- Hoya dickasoniana
- Hoya dimorpha
- Hoya diptera
- Hoya dischorensis
- Hoya diversifolia (Thailand, Malaysia, Indonesia, Philippines)
- Hoya dolicosparte
- Hoya edenii
- Hoya eitapensis
- Hoya elliptica (Thailand, Malaysia, Philippines)
- Hoya endauensis
- Hoya engleriana
- Hoya erythrina
- Hoya erythrostemma (Thailand)
- Hoya eitapensis
- Hoya excavata
- Hoya filiformis
- Hoya finlaysonii
- Hoya fischeriana (Philippines)
- Hoya fitchii (Philippines)
- Hoya flagelleta
- Hoya flavescens
- Hoya flavida
- Hoya fraterna
- Hoya fungi
- Hoya fusca
- Hoya fuscomarginata
- Hoya gigantangensis - syn. Hoya benitotanii (Philippines)
- Hoya gigas
- Hoya gildingii
- Hoya glabra
- Hoya globulosa
- Hoya golamcoiana (Philippines)
- Hoya gonoloboides
- Hoya gracilis - invalid name, syn. Hoya memoria (Philippines)
- Hoya graveolens
- Hoya greenii (Philippines)
- Hoya grifithii
- Hoya guppyi
- Hoya halconensis (Philippines)
- Hoya halophila
- Hoya hasselti
- Hoya heuschkeliana (Philippines)
- Hoya heuschkeliana ssp. cajanoae (Philippines)
- Hoya heuschkeliana ssp. heuschkeliana (Philippines)
- Hoya hellwigiana
- Hoya hypolasia (Papua New Guinea)
- Hoya imbricata - syn. Hoya pseudomaxima (Indonesia, Philippines)
- Hoya imperialis (Philippines, Malaysia)
- Hoya imperialis ssp. rauchii (Malaysia)
- Hoya inconspicua
- Hoya incrassata (Philippines)
- Hoya incurvula
- Hoya ischnopus
- Hoya javanica - syn. Hoya multiflora (Malaysia)
- Hoya juanngoiana (Philippines)
- Hoya kanyakumariana
- Hoya kastbergii
- Hoya kenejiana
- Hoya kentiana (Philippines)
- Hoya kerriiHoya kerriiHoya kerrii is a species of Hoya native to the south-east of Asia. It is dedicated to Arthur Francis George Kerr, british physician, plants collector and author of books about botany....
- Heart Hoya (Philippines, Thailand) - Hoya kloppenburgii (Malaysia)
- Hoya krohniana (Philippines)
- Hoya kuhlii
- Hoya lacunosa
- Hoya lacunosa ssp. lacunosa
- Hoya lacunosa ssp. pallidiflora
- Hoya lambii
- Hoya lamingtoniae
- Hoya landgrantensis (Philippines)
- Hoya lasiantha
- Hoya latifolia
- Hoya lauterbachii
- Hoya lazaroi (Philippines)
- Hoya leytensis (Philippines)
- Hoya limoniaca
- Hoya linavergariae (Philippines)
- Hoya linearis
- Hoya litoralis
- Hoya lobbii
- Hoya loheri (Philippines)
- Hoya longifolia
- Hoya lucardenasiana (Philippines)
- Hoya lucyae (Philippines)
- Hoya macgillivrayiHoya macgillivrayiHoya macgillivrayi is a fast growing vine native to northeastern Australia. It has oval pointed leaves and has a twining growth habit. The flowers of the plant are approximately 6 cm in diameter and vary slightly in size, shape, and color from each cultivar. They come in umbels of 6 to 10...
- Hoya macgregorii (Philippines)
- Hoya macrophylla
- Hoya madulidii - syn. Eriostemma madulidii (Philippines)
- Hoya magnifica
- Hoya megalaster
- Hoya melifluaHoya melifluaHoya meliflua is a vine native to the Philippines. It has stiff succulent leaves with a very clean look to them with no venation. The flowers are reddish orange and have nectaries near the base of the central column from which a dark sap is produced that stains very easily...
(Philippines) - Hoya meliflua ssp. fraterna (Philippines)
- Hoya meliflua ssp. meliflua (Philippines)
- Hoya membranifolia
- Hoya memoria (Philippines)
- Hoya meredithii
- Hoya merrillii (Philippines)
- Hoya micrantha
- Hoya microphylla
- Hoya microstemma
- Hoya minahassae
- Hoya mindorensis (Philippines)
- Hoya minibelle
- Hoya mitrata (Malaysia)
- Hoya monetteae (Philippines)
- Hoya montana
- Hoya motoskei - Spotted Waxplant
- Hoya multiflora - Shooting Star Hoya (Malesia)
- Hoya myrmecopa (Indonesia, Philippines)
- Hoya naumanii
- Hoya nabawanensis
- Hoya neo-caledonica
- Hoya neo-ebudica
- Hoya nicholsoniae
- Hoya nummularioides
- Hoya nyhuusiae
- Hoya oblongata
- Hoya obovata
- Hoya obscuraHoya obscuraHoya obscura is a fast growing hoya from the Philippines. Characterized by medium-sized veined leaves that range from deep green when grown in shade, to a deep reddish color when grown in sunlight. This hoya is very easy to grow....
(Philippines) - Hoya obtusifolia
- Hoya obtusifolioides
- Hoya odetteae (Philippines)
- Hoya odorata (Philippines)
- Hoya onychoides
- Hoya oreogena
- Hoya ovalifolia
- Hoya pachyclada
- Hoya padangensis
- Hoya palawanica' (Philippines)
- Hoya pallilimba
- Hoya panayensis (Philippines)
- Hoya panchoi (Philippines)
- Hoya pandurataHoya pandurataHoya pandurata is a species of plant in the Asclepiadaceae family. It is endemic to China.-Source:* China Plant Specialist Group 2004. . Downloaded on 22 August 2007....
- Hoya parasitica
- Hoya parviflora
- Hoya patella
- Hoya pauciflora
- Hoya paxtoni
- Hoya paziae (Philippines)
- Hoya pentaphlebia (Philippines)
- Hoya picta
- Hoya pimenteliana (Philippines)
- Hoya platycaulis (Philippines)
- Hoya plicata
- Hoya polystachya
- Hoya polyneura - Fishtail Hoya
- Hoya pottsii
- Hoya praetorii
- Hoya pseudo-littoralis
- Hoya pubera
- Hoya pubicalyx (Philippines)
- Hoya pulchella
- Hoya purpurea
- Hoya purpureo-fusca
- Hoya pusilla
- Hoya querinoensis
- Hoya quinquenervia (Philippines)
- Hoya quisumbingii (Philippines)
- Hoya ramosi
- Hoya retusa
- Hoya revoluta
- Hoya ridleyi
- Hoya rigida
- Hoya rotundifolia
- Hoya ruscifolia - syn. Dischidia ruscifolia
- Hoya salweenica
- Hoya samoensis
- Hoya schneei
- Hoya scortechinii
- Hoya serpensHoya serpensHoya serpens is a small trailing vine found in the Himalayas and surrounding areas. It has small round leaves that are 1.5 to 2 cm long. The leaves are dark green, hairy, and has grey spots intermittently dispersed....
- Hoya shephardell
- Hoya shepherdii - String Bean Hoya
- Hoya shortechinii
- Hoya siamicaHoya siamicaHoya siamica is a slender vine found in Thailand with long light green leaves. The leaves are on average 1.5-2 cm wide by 4-10 cm long. It has white flowers that come in clusters of 10 to 15. The corolla of the flowers are white and flat; the corona can be a deep purple or a very pale yellow...
- Hoya siariae (Philippines)
- Hoya sigillatis
- Hoya sipitangensis
- Hoya solaniflora
- Hoya soligamiana (Philippines)
- Hoya spartioides
- Hoya stoneiana
- Hoya subcalva
- Hoya subglabra
- Hoya subquintuplinervis
- Hoya surigaoensis (Philippines)
- Hoya sussuela
- Hoya telosmoides
- Hoya teretifolia
- Hoya thailandica
- Hoya thomsonii
- Hoya tomataensis
- Hoya tsangii (Philippines)
- Hoya uncinata
- Hoya vaccinioides
- Hoya vanuatuensis
- Hoya verticillata (Philippines)
- Hoya viracensis
- Hoya vitchii
- Hoya vitellina
- Hoya vitellinoides
- Hoya vitiensis
- Hoya wallichii
- Hoya walliniana
- Hoya wayetii (Philippines)
- Hoya waymaniae
- Hoya weebella
- Hoya whistleri
- Hoya wibergiae (Philippines)
- Hoya wightii