Many animals are on the verge of extinction. Do plants face the threat of extinction too? A quarter of all plants in the world are known to be in danger or threatened with extinction.
However, the true number is probably much higher because thousands of species have not yet been identified.
The main dangers to plants are habitat destruction, the spread of towns, and modern farming techniques, which include the use of pesticides.
Two-thirds of the world's plants, including many endangered spe cies, grow in the tropics where their rainforest habitat is threatened.
Some plants are threatened by over-collection or the introduction of plant-eating animals such as goats. Plants introduced from other countries can also overwhelm native species.
About one-third of all threatened plants grow on islands. The bottle palm, for example, is particularly vulnerable because it only lives on one small island off the coast of Mauritius.
Other plants in danger include the South American slipper orchid, Hawaiian silversword, wild coffee plant and rosy periwinkle.