NATURAL HISTORY OF PLANTS. 



VIII. OALLITRICHE^. 



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

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

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

 confluent above. Germen 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 descendent ; 

 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 dry, dorsally margi- 

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

 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 axillary solitary or few ; bractlets mem- 

 braneous. {All îvarm and temp, rccfions.) See p. 151. 



