Cryptostegia is a genus of flowering plant

Flowering plant

The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

s in the dogbane

Apocynum

Apocynum, commonly known as Dogbane and Indian Hemp, is a genus of the plant family of the Apocynaceae with seven species. From the Greek: apo, away; cyno, dog, attributed to its toxicity...

 family, 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...

. It consists of three species of thin, many-stemmed, woody, perennial 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 native to tropical Africa

Tropical Africa

Although tropical Africa is most familiar in the West as depicted by its rain forests, this region of Africa is far more diverse. While the tropics are thought of as regions with warm to hot moist climates caused by latitude and the tropical rain belt, the geology of areas, particularly mountain...

 and Madagascar

Madagascar

The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

. The milky sap, that oozes from the stems or leaves, is extremely toxic to all livestock. It contains cardiac glycosides which causes sudden death after exercise. Though the sap is also some quality latex, there is no commercial use for its production. These evergreen plants are grown for their showy ornamental vines. They are vigorous, self-supporting, beautiful vines that could reach 15m in length. Leaves are ovate, glossy, dark green 6-10 cm long and 3-5 cm wide and in opposite pairs. Clusters of attractive, large, showy, funnel-shaped flowers with 5 white to rose-pink or reddish-purple petals bloom in summer after the wet season. Seed pods are rigid 10-12 cm long and 3-4 cm wide, and grow in pairs at the end of a short stalk with silky white floss. The plants are rampant growth and are invasive

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 in some areas. In Australia

Invasive species in Australia

Invasive species are a serious threat to the native biodiversity of Australia and are an ongoing cost to Australian agriculture.Management and the prevention of the introduction of new invasive species are key environmental and agricultural policy issues for the Australian federal and state...

, they are threatened as some of a most restricted weeds.

In cultivation, the plants prefer a hot climate.

Species

• Cryptostegia grandiflora R.Br. – Purple Allamanda, Rubber Vine
• Cryptostegia madagascariensis Bojer ex Decne.