NUDIFLOR^ 365 



in the fresh-water aquatic formation, in waters rela- 

 tively rich in mineral salts, in nearly stagnant waters 

 in the free floating-leaf association, and in the open 

 reed-swamp. 



The plant has the floating habit. The roots are 

 solitary. The frond is thin, membranous, transparent, 

 inversely ovate, elliptic to lance-shaped, tailed one 

 end, serrate the other. The fronds are proliferous at 

 right angles, giving the ivy-leafed appearance. 

 Autumnal bulbils are produced which survive the 

 winter. There is a groove under the edge of the 

 frond and in this branches arise which remain in 

 union with the parent shoot. The young frond is 

 arrow-shaped, and persistent. The frond is narrowed 

 at the base, with no epidermis, proliferous on one or 

 both sides. The young fronds are numerous. They 

 may reach a length of six lines and are half as broad 

 when fully developed. 



The flowers are borne in the grooves. The spathe is 

 reduced, with two male flowers reduced to one stamen 

 and one female flower with one carpel. The style is 

 very short. The ovary has a single ovule. The testa 

 is rough and grooved. 



This is a floating plant of no appreciable height. 

 It flowers in June and July, and is a herbaceous 

 annual reproduced by shoots. 



The plant is monoecious. It is half-submerged, 

 and if pollen is produced it may be carried by small 

 insects, but it is probable that the plant is propagated 

 almost entirely by autumnal bulbils. 



