MICROSPERME.E 281 



precaution suggested should, however, always be 

 taken. 



Ponds, ditches, are the habitat of the Frogbit. It 

 occurs in the fresh-water aquatic formation, in waters 

 relatively rich in mineral salts, in still or nearly stag- 

 nant waters in the floating-leaf association. 



The plant is rootless, or may have fibrous roots. 

 The stems are bulbiferous, stoloniferous, the stolons, 

 which are horizontal, being produced in summer. 

 Hibernacula or resting-buds are produced in autumn, 

 on the stolons. These fall off and winter in the mud, 

 and in the spring float up and form new plants. The 

 leaves are rounded or kidney-shaped, stalked, entire, 

 heart-shaped below, deep green above, purplish below, 

 rather thick and leathery. 



The flowers are erect, formed on the surface of the 

 water. The flower-stalks in the male flowers are 

 short, and there are two to three large flowers on long, 

 ultimate flower-stalks, with a membranous spathe 

 at the base of two thin bracts. The three outer 

 perianth-segments are pale green, small and oblong. 

 The three inner are broadly inversely ovate, crumpled. 

 There are three to twelve stamens. The spathe in 

 the female flowers is stalkless among the leaves. 

 The flower-stalk is enlarged at the tip into a short 

 perianth-tube, which encloses the ovary. There are 

 six styles. The stigma is bifid. The fruit is dry, 

 six-celled, and contains many seeds. The prominent 

 cells of the testa swell in water and a spiral thread 

 projects. 



