SCIENCE AND INDUSTRY. 
: The Water Hyacinth. 
By EWEN MACKINNON, B.A., B.Sc. 
HE WATER HYACINTH—Hichhornia speciosa (Kunth) (== Pontederia 
3| crassipes (Mart.)) is a floating representative of a small order of 
plants known as the Pontederiacew, named in honour of Pontedera, a 
professor of botany at Padua, 200 years ago. There is only one 
species of this order native in Northern Australia and Queensland, but 
none in New South Wales or Victoria. Our plant, like many more 
of the plant pests of Australia—notably, Prickly Pear, the Lantana, 
and the Cape Weed—is an introduced species, and has been distributed from 
Queensland into New South Wales and Victoria. Its native home is Guiana, in 
THE WATER HYACINTH. 
South America, the whole order consisting of aquatic and marshy plants dis- 
tributed throughout the warm parts of the world. Such introduced plants often 
become far greater pests in their new situations than in their native habitats. 
They escape from the old ecological factors which have brought about a state 
of equilibrium; and, finding the new conditions favorable, develop to such an 
extent as to become a nuisance. In their new environment they will come 
naturally into a new strugele for existence, resulting finally in a new balance 
of nature; but we cannot afford to wait for this, and man becomes a new and 
necessary factor in their control. The water hyacinth, however, has not failed 
to make its presence felt in its own home, and in some parts of Guiana it is 
as great a pest as anywhere else in the world. Though called a hyacinth, it is 
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