ONAGRARIACEM. 501 



19. Myriophyllon Vaill. — Flowers monoecious or polygamous, 

 4-merous ; receptacle in males slightly, iu females very concave, 4- 

 sulcate. Sepals 4, or more rarely 2. Petals 2-4, imbricate (in 

 female flower smaller). Stamens 2-4 or 6-8, 2-seriate; anthers 

 elongate basifixed, laterally 2-rimose (in female flower sterile, rudi- 

 mentary or 0). Germen entire, 2-4 locular, in male flower very 

 short effete or 0); styles as many short, generally recurved, plumose 

 at apex. Ovules in cells 1, more rarely 2, descending ; raphe dorsal. 

 Fruit nutlike or drupaceous; flesh scanty; putamen crustaceous. 

 Seeds oblong ; testa membranous ; albumen copious fleshy ; embryo 

 axile cylindrical. — Glabrous aquatic herbs ; branches often floating ; 

 leaves alternate, opposite or verticillate, entire or dentate, serrate or 

 pectinately pinnatifid ; flowers in axils of leaves sessile or shortly 

 pedicellate, sometimes in terminal bracteate spikes; the lower female ; 

 the upper male ; the intermediate often hermaphrodite. (All warm 

 and cold aquaiic regions.) — See p. 480. 



20. Serpicula L. — Flowers (nearly of Myriophyllon or Hal or agis) 

 monoecious ; receptacle of males very short. Sepals 4 and petals 

 same cucullate or concave. Stamens 8. Rudiment of gynsecium 

 short ; styles 4, more or less developed. Receptacle of female flower 

 sacciform subovoid ; sepals 4 and petals same. Stamens rudimentary 

 or 0. Gyncecium, fruit, seeds, etc., of Haloragis. — Low creeping or 

 decumbent branched herbs ; leaves opposite and alternate, subsessile 

 entire or dentate ; flowers (minute) axillary glomerulate ; females 

 sessile ; males few or 1, long pedicellate. (Africa, trop, marshy Asia 

 and America.) — See p. 481. 



21. Proserpinaca L. — Flowers hermaphrodite (nearly of Halo- 

 ragis), 3-4-merous, apetalous, 3-4-androus. Germen 3-4-locular ; 

 styles, ovules, fruit, etc., of Haloragis (or Myriophyllon). — Glabrous 

 aquatic herbs ; stem decumbent at base ; leaves alternate lanceolate 

 dentate or pectinately pinnatifid ; flowers (minute) axillary, solitary 

 or glomerulate. (Warm North America, Antilles.) — See p. 482. 



VI. GUNNERE^E. 



22. Gunnera L. — Flowers hermaphrodite or monoecious ; recep- 

 tacle concave obovoid or compressed, enclosing adnate germen. 



