450 HYDROCHARIDACE^.. (fUOG's-BIT FAMILY.) 



Order 140. HYDROCIIARIDACE^. (Frog's-bit 



Family.) 



Aquatic herbs, with monoecious or dicccious flowers, from a membrana- 

 ceous spathc. Sepals and petals 3, or the latter wanting, distinct in the 

 sterile flower, united into a tube in the fertile, and coherent with the 1-9- 

 cellcd ovary. Stamens 3-12. Ovules numerous, ascending, ortliotropous. 

 Stigmas 3-9. Fi-uit indehisccnt, many-seeded. Embryo straight, without 

 albumen. 



Synopsis. 



* Orary l-celled. Stigmas 3. 



1. ANACriARIS. Flowers pol3'gamo-dicecious. Spathe sessile. Stamens 9. Leaves short, 



opposite or whorled. 



2. VALLISNERIA. Flowers dioecious. Spathe peduncled. Stamens 3. Leaves long, linear. 



* * Cells of the ovary and stigmas 6-9. 



3. LIMNOBIUM. Flowers monoecious. Stamens G-9, monadelphous. Leaves cordate, 



pctioled. 



1. ANACHARIS, Rich. 



Flowers diceciously polygamous, enclosed in the bud in a 2-clcft axillary 

 Bessile spathe. Sterile flowers minute. Sepals and petals 3. Anthers 9. Fer- 

 tile flowers pistillate or perfect. Sepals and petals united into a very long and 

 slender G-i)artcd tube. Stamens 3-6, perfect or sterile. Ovary l-celled, with 

 three parietal j)lacenta;, fcw-ovuled. Style capillar}', adnate to the tube. Stig- 

 mas 3, each 2-lobcd, exserted. Fruit oblong, coriaceous. — Perennial herbs, 

 with elonjratcd filiform branching immersed stems, and small and very numer- 

 ous opposite or wiiorled leaves. Fertilization eff"cctcd by the sterile flowers 

 breaking away from the stem, and expanding at the surface among the floating 

 stigmas. 



1 . A. Canadensis, Planch. Stem much branched ; leaves 3-4 in a 

 wborl, sessile, varying from linear to elliptical, 1-nervcd, pellucid and minutely 

 serrulate. (Udora Canadensis, Niitt.) — In slow-flowing streams and ponds, 

 Clierokcc, North Carolina, Curtis, and northward. July and Aug. — Leaves 

 3"-G" long. 



2. VALLISNEHIA, IMicbcli. TAnc-GUASs. 



Flowers ditt'cious Sterile flowers numerous, minute, crowded on a spadix, 

 which is enclosed in an ovate 3-leavcd short-stalked spathe. Calyx 3-parted. 

 Corolhi none. Stamens 3. Fertile flowers solitary, enclosed in a tui)ular spathe, 

 and liorne on a very lonj; and mostly spiral scape. Sepals and small petals 3, 

 united and (oiiercnt with the cylindrical l-celled many-ovuled ovary. Stifjmas 

 .*>, crtfli :' lobed Seeds numerous, fixed to tinx'e parietal placenta;. — Acjuatic 

 hcrlt", Willi cree[iiiijj: steni«, anrl elonj^ated stra|)-sliapcd leaves. Fertilization 

 cfl'cct<.d mosily us in Anaeliaris. 



