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Biological Diversity:
T H E O L D E S T H U M A N H E R I T A G E
By
Edward O. Wilson
In the northeastern United States, as in most of the remainder of the country,
about one plant species in five is threatened with significant reduction in numbers
or even with total extinction. Here are the names of several: New England boneset,
Furbish’s lousewort, threadleaf sundew, fairy wand and hairy beardtongue. Many
people still ask the vexing question: Of what possible value, except to a few
botanists, is a plant with a name like hairy beardtongue? Why should money and
effort be spent to save this and other bits of floristic esoterica?
Let me tell the ways. Consider periwinkles of the genus Catharanthus, flowering
plants that live on Madagascar, a great island off the East Coast of Africa. Inconspicuous
in appearance, located all the way around the world, the six species of periwinkles
would seem to be even less worthy of attention than beardtongues and louseworts.
But one of them, the rosy periwinkle (Catharanthus roseus), is the source of alkaloid
chemicals vinblastine and vincristine, used to cure two of the most deadly forms of
cancer: Hodgkin’s disease, especially dangerous to young adults, and acute lymphocytic
leukemia, which, before the periwinkle alkaloids, was a virtual death sentence
for young children. These anti-cancer substances are now the basis of an industry
earning more than 100 million dollars a year. Ironically, the other five periwinkle
species remain largely unexamined for their medical potential. One of them is near
extinction due to the destruction of its habitat on Madagascar. On a global scale,
one out of ten plant species has been found to contain anti-cancer substances of
B i o l o g i c a l
1 D i v e r s i t y