MEDICINAL AND AROMATIC CROPS (2+1)

Description of the plant

• Plants of the genus Dioscorea, commonly called medicinal yams, are perennial, climbing herbs with tubers or rhizomes.
  

• Approximately 600 species have been reported to occur throughout the world, mostly in tropical and subtropical regions and, to a limited extent, in temperate regions also.

• Of these, only 15 species are known to contain steroidal sapogenins, chiefly diosgenin. Out of the various species tested, D. composita and D.floribunda found growing wild in Central America and D. deltoidea, found in the North-western Himalayas, are the main species from which diosgenin is extracted commercially. All the three species are dioecious.