AQUATIC PLANTS OF FRESHWATER 



scape of about their own length, with recurved stigmas. Only one species 

 is known in the United States, which occurs in shallow streams from 

 Massachusetts to Northern New York, Ontario and Minnesota to Georgia, 

 Alabama and Kentucky. Flowers July and August. 



A few stalks of Ceratophyllum make a fine appearance in the aquarium, 

 as the growth there developed is more delicate, brighter green and finer in 

 appearance than that of the ditch, pond or stream. 



HIPPURIS 



This genus consists of a small group of aquatic herbs with simple 

 erect stems and verticillate entire leaves, small axillary flowers and a one- 

 celled, one-seeded fruit. There are three known species native to north 



temperate and lower arctic regions and southern 

 South America. 



Hippuris vulgaris (Linn.) or Bottle Brush, 

 Joint-weed, Mare's tail, etc., Fig 126, has a slender 

 stem and linear or lanceolate acute leaves in crowned 

 whorls or verticils. The flowers have stamens with 

 a short thick filament, comparatively large two- 

 celled anthers and ovoid seeds hollow in the interior. 

 The plant is native to swamps and bogs in Labrador 

 and Greenland to Alaska; south to Maine along the 

 shore of Lake Superior, in the Rocky Mountains to 

 New Mexico and along the Pacific Coast. 



Hippuris tetraphyllum (Linn.) H. maritema 

 (Hell.)or Four-leaved Mare's tail, is a smaller species 

 with obovate or oblanceolate entire leaves in verticils 

 of 4's and 6's at the base of the stem. Native to 

 Labrador and Canada to the United States border 

 and in Alaska. 



Hippuris has the character of Anacharis cana- 

 densis, but is larger, stifFer and more erect, growing 

 12 to ic inches above the water. It largely takes 



FIG. iz6. Mare's Tail, ^ « , • • i J 



Hippurh -vuigaru, and enlarged the place of Anachatis m northern waters and was 



fruit. Reduced one-half. j^jroduced into the Middle States by aquarium 



fanciers in 1 898, but has recently been superseded by A. canadensis gigantea. 



FONTINALIS 



This genus of aquatic moss contains a quite considerable number of 

 universally distributed freshwater species, two or three of which thrive in the 

 aquarium. Ten species are recognized as native to the United States and 



199 



