Hoya (plant)

Template:Short description Template:Use dmy dates Template:Automatic taxobox

Hoya is a genus of over 500 species of plants in the dogbane family, Apocynaceae, commonly known as waxflowers.<ref name="FoA">Template:Cite web</ref> Plants in the genus Hoya are mostly epiphytic or lithophytic vines, rarely subshrubs, with leathery, fleshy or succulent leaves, shortly tube-shaped or bell-shaped flowers with five horizontally spreading lobes, the flowers in umbels or racemes, and spindle-shaped or cylindrical to oval follicles containing flattened egg-shaped to oblong seeds.<ref name="FoA" /><ref name="RBGS">Template:Cite web</ref><ref name="NT">Template:Cite web</ref>

Description

Plants in the genus Hoya are mostly epiphytic or lithophytic vines that rarely form roots in the ground, or rarely more or less shrubby. They have creeping or climbing, pendent, left-twining stems, with white latex, and sometimes with adventitious roots. The stems are cylindrical in cross section, and more or less sparsely branched. The leaves are leathery, often fleshy or succulent, elliptic, egg-shaped, rhomboid or lance-shaped, may be glabrous or hairy, and usually have a petiole.<ref name="FoA" /><ref name="RBGS" /><ref name="NT" /><ref name="Albers">Template:Cite book</ref><ref name=FB>Template:FloraBase</ref>

The flowers are often fleshy or waxy, arranged in umbels or racemes on a peduncle between the leaves, the peduncle usually persisting from year to year. The petals are wheel-shaped or tube-shaped, with five fleshy, more or less jug-shaped, horizontally spreading lobes attached to the staminal column, and forming a prominent ring alternating with the petal lobes.<ref name="FoA" /><ref name="RBGS" /><ref name="NT" /><ref name="Albers" /><ref name="FB" />

The fruit is a spindle-shaped to oval follicle containing flattened, egg-shaped to oblong seeds with a tuft of hairs at one end.<ref name="FoA" /><ref name="NT" /><ref name="Albers" />

Taxonomy

The genus was first formally described in 1810 by botanist Robert Brown in his book Prodromus Florae Novae Hollandiae et Insulae Van Diemen,<ref name="R.Br.">Template:Cite book</ref> and honours Thomas Hoy, the gardener for the Duke of Northumberland.<ref name="FoA" /> The first species of Hoya that Brown described (the type species), was Hoya carnosa.<ref name="R.Br." />

Species list

Template:Main

Use in horticulture

Many species of Hoya are popular houseplants in temperate areas (especially H. carnosa), grown for their attractive foliage and strongly scented flowers. Numerous cultivars 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 ('Tricolor', 'Rubra' & 'Compacta'), H. pubicalyx (often mislabelled as H. carnosa or H. purpurea-fusca), and H. kerrii. Hoyas are easy to propagate, and are commonly sold as cuttings, either rooted or unrooted, or as a potted plant.Template:Citation needed

Hoya carnosa has been shown in recent studies at the University of Georgia to be an excellent remover of pollutants in the indoor environment.<ref name="UGA">Template:Cite news</ref>

Various cultures have used hoyas medicinally, especially Polynesian cultures.Template:Citation needed Some are toxic to livestock and sheep poisonings in Australia are reported.Template:Citation needed

Several Hoya species and cultivars are excellent terrarium plants.Template:Citation needed

Rachel Colette Conroy was appointed the International Cultivar Registration Authority for Hoya in 2023.<ref>Template:Cite web</ref>