434 THE HYDEOCHAEIS FAMILY. [Elodea. 



surface of the water, where it terminates in 3 or 6 small, spreading seg- 

 ments. Anacharis Alsinastrum, Bab. 



In ponds, canals, and slow streams, abundant in North America, and 

 introduced from thence into Britain, where it was first observed in 1847 

 in Yorkshire, Leicestershire, and near Berwick. It has since spread 

 with great rapidity, and there are now but few counties without it. 

 [Generally known as the American Water-weed.} Fl. summer and autumn. 



II. HYDROCHAEIS. FEOGBIT. 



A single species, distinguished as a genus from Stratiotes and others 

 more by its habit than by any very marked characters in the flower. 



1. H. Morsus-ranse, Linn. (fig. 979). Frogbit. Stems floating, 

 resembling the runners of creeping plants, with floating tufts of radical 

 leaves, peduncles, and submerged roots. Leaves stalked, orbicular, 

 entire, cordate at the base, rather thick, about 2 inches diameter. 

 Peduncles of the male plant rather short, bearing 2 or 3 rather large 

 flowers on long pedicels, enclosed at the base in a spatha of 2 thin 

 bracts. Outer segments of the perianth pale green, shorter and 

 narrower than the inner white ones. Stamens 3 to 12. Female spatha 

 sessile among the leaves ; the flowers like the males, but with the 

 pedicel enlarged at the top into a short perianth-tube enclosing the 

 ovary. Styles 6, with 2-cleft stigmas. Fruit dry, 6-celled, with several 

 seeds. 



In ditches and ponds, dispersed over Europe and central and Eussian 

 Asia, but not extending to the Arctic Circle. Occurs in many parts of 

 England and Ireland, not indigenous in Scotland. Fl. summer. 



III. STEATIOTES. WATEE-SOLDIEE. 



A single species, with the flowers nearly of ffydrocharis, but with a 

 succulent fruit, and a very different habit. 



1. S. aloides, Linn. (fig. 980). Water- soldier. Eootstock creeping 

 in the mud, producing at the bottom of the water tufts of sessile, long 

 and narrow, more or less succulent leaves, bordered by small, pointed 

 teeth. Peduncles rising from among the leaves to a few inches above 

 the water, much thickened at the top, bearing a spatha of 2 bracts, 

 about an inch long. Male flowers several in the spatha, stalked, much 

 like those of ffydrocharis, but rather larger, with usually 12 or more 

 stamens. Female flowers solitary, and sessile in the spatha, with a 

 rather long tube, swollen below the middle. Ovary and stigmas nearly 

 as in Hydrocharis, but the fruit is ovoid and somewhat succulent. 



In lakes and watery ditches, dispersed over Europe and Eussian Asia, 

 except the extreme north. Common in the fens of eastern England, 

 occurs also in Lancashire and Cheshire, and naturalised in Ireland and 

 Scotland. & tuvmer. 



