82 



THE AMERICAN BOTANIST 



flowers are so insignificant and so rarely produced that we mav 

 possibly not think of them as belonging to this class. Several 

 of the bladderworts { Utricniaria) also float and in the tropics 

 the water lettuce {Pisfia spafJuilata ) , a relative of Jack-in-the- 

 pulpit, may be found thriving on the surface of pools and slow 

 streams. The most singular of these floating plants, however, 

 is doubtless the water hyacinth {Piaropus crassipcs). Though 

 a plant of considerable size, it has no difficulty in maintaining 

 its position in the water, being buoyed up by its curious leaf- 

 stalks wdiich are dilated at the base and filled with air. The 

 rootstalk from wdiich these leaves rise is able to produce roots 

 on occasion and when, through stress of circumstances, the 

 plant finds itself stranded on a muddy shore it promptly sends 

 out roots and lives as an anchored plant thereafter, though 

 usually it is found floating. In favorable situations it may 

 completely cover the water for long distances. 



The water hyacinth is frequently seen in cultivation in the 

 Northern States, and several dealers in aquatics offer it for 

 sale. In the tropics, however, it is a most detested weed with- 

 out value. In some Florida rivers it has proved such an ob- 

 stacle to navigation that the national government has found it 

 necess'ary to take strenuous measures to eradicate it. It is a 

 native of tropical America and, though commonly cultivated in 

 this country, the plant seems not to have taken up a wild life 

 here until about 1800. Then it escaped from an artificial pool 

 into- the St. John's river in Florida and has since spread to the 

 bayous and tidewater marshes as far as Louisiana. 



In spite of its aggressive methods of colonization, the 

 plant presents a beautiful sight when in full bloom, being 

 thickly set with short spikes of purplish-lavender flowers held 

 well above the water. The individual flowers are large and 

 slightly two-lipped with the middle of the upper petal marked 

 with deep blue and yellow. The leaf blades are rounded and 

 somewhat spoon-shaped while the petioles bulge out into a 



