•256 NATURAL HISTORY OF PLANTS. 



VIII. CALLITRICHE^. 



150. Callitriche L. — Flowers monoecious or more rarely poly- 

 gamous ; sepals (?) 2, lateral. Stamens 1, or 2, alternisepalous ; fila- 

 ments elongate ; clefts of 2-locular reniform anthers lateral, finally 

 confluent above. Germ en sessile or shortly stipitate ; cells 2, oppo- 

 sitisepalous ; style branches 2, elongate subulate-filiform, stigmati- 

 ferous on all sides ;. ovules in each cell 2, collaterally desceudent ; 

 micro pyle extrorse superior ; obturator often minute ; a spurious 

 septum possibly springs from back of cells and intrudes between the 

 ovules. Fruit hence 4-lobed, 4;-locellate ; lobes cby, dorsally margi- 

 nate or winged, finally solute; cells 1-spermous; seed desceudent; 

 testa membraneous ; albumen fleshy ; cotyledons of straight or curved 

 axile terete embryo equal to radicle. — Annual subglabrous herbs 

 usually aquatic very slender ; leaves opposite linear or obovate 

 entire 3- nerved flowers axiUary solitary or few ; bractlcts mem- 

 braneous. {All warm and temp, regions.) See p. 151. 



