Endangered Plants 213 Encephalartos is the second largest genus in the Cycad genera All Encephalartos are endemic to the African continent, with most in xeric habitats Natural populations of Encephalartos suffer intense pressure from plant collectors Africa Encephalartos species with male cones Swaziland South Lesotho Africa Figure Encephalartos longifolius (Photograph courtesy of Dr D A Steingraeber.) Brittle greenhood (Pterostylis truncata) is a clonal orchid, found in New South Wales and Victoria, Australia Causes of this orchid’s decline include overgrazing by feral goats and European rabbits and the introduction of a highly invasive weed into its habitat Australia NORTHERN TERRITORY WESTERN AUSTRALIA QUEENSLAND SOUTH AUSTRALIA NEW SOUTH Newcastle Sydney WALES Pterostylis truncata VICTORIA Wollongong Canberra TASMANIA Figure Pterostylis truncata Less than 10% of named plant species have been analyzed for medicinal or nutritional properties (Stermer, 1995) Nonetheless, 25–40% of all drug prescriptions in the United States contain plant ingredients (Durant and Saito, 1985), and many of these ingredients cannot be synthetically made About 80% of people in developing countries use traditional medicines As more and more plant species go extinct, so may our chances to find the next heart medicine (e.g., Digitalis; foxglove) or treatment for childhood leukemia (from Catharanthus roseus; the rosy periwinkle) To improve the effectiveness of biodiversity conservation, increased emphasis is needed on systematic surveys and monitoring Many species may be classified as rare owing to poor surveys, as evidenced by the rate of species discoveries