Distribution of Asclepiadaceae:
The family Asclepiadaceae is commonly known as ‘Milk weed family’. In includes 320 genera and 2,000 species of worldwide distribution, but mostly confined to tropics and sub-tropics. In India 332 species belonging to 35 genera are found.
Economic Importance of Asclepiadaceae:
- Food: Gymnema lactiferum yields latex which is used as food in Ceylon.
- Fibers: Some plants like Daemia extensa, Calotropis procera, C. gigantea, Marsdenia and Leptadenia etc. yield silky fibers which are used for making ropes, mat, stuffing pillows etc.
- Medicinal: The source of medicine in the family is latex from which alkaloids are extracted. The roots of Oxystelma esculentum are specific for jaundice. The roots of Pentatropis are used in gonorrhoea. Hemidesmus indicus is used in leucorrhoea, rheumatism and in snake bites. Daemia extensa is used in cough; asthma and diarrhoea.
- Rubber: Cryptostegia grandiflora is a natural source of rubber in India.
- Poison: Some species of Asclepias are important as live-stock poison. The sap of Matelea has been used as an arrow poison.
- Ornamental: Asclepias, Cryptostegia, Hoya, Huernia, Ceropegia, Periploca etc. are cultivated for ornamental purposes.
Affinities of Asclepiadaceae:
The family Asclepiadaceae is closely allied to the family Apocynaceae, from which it differs in following respects:
- Absence of pollinia in the Apocynaceae.
- No translator mechanism in the Apocynaceae.
- In Apocynaceae stamens are not fused with stigma to form gynostegium. Rest of the phylogeny has been discussed under Apocynaceae.