450 EIYDROCnAIUDACEjE. (fROG's-BIT FAMILY.) 



Order 140. HYDROCIIARIDACEiE. (Frog's-bit 

 Family.) 



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

 ceous spathe. 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- 

 celled ovary. Stamens 3-12. Ovules numerous, ascending, orthotropous. 

 Stigmas 3-9. Fruit indehiscent, many-seeded. Embryo straight, without 

 albumen. 



Synopsis. 



* Ovary 1-celled. Stigmas 3. 



1. ANACIIARIS. Flowers polyganio-diceeious. Spathe sessile. Stamens 9. Leaves short, 



opposite or whorled. 



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



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



3. LIMXOBICM. Flowers monoecious. Stamens 6-9, monadelphous. Leaves cordate, 



petioled. 



1. ANACHAMS, Pich. 



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

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

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

 slender 6-parted tube. Stamens 3-G, perfect or sterile. Ovary 1-celled, with 

 three parietal placentae, few-ovuled. Style capillary, adnate to the tube. Stig- 

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

 with elongated filiform branching immersed sterns, and small and very numer- 

 ous opposite or whorled leaves. Fertilization effected 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 

 whorl, sessile, varying from linear to elliptical, 1 -nerved, pellucid and minutely 

 serrulate. ( Udora Canadensis, Nutt.) — In slow-flowing Streams and ponds, 

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



3"-G" lung. 



2. VALLISNERIA, Micheli. Tape-grass. 



Flowers diocious. Sterile flowers numerous, minute, crowded on a spadix, 

 which is enclosed in an ovate 3-leaved short-stalked spathe. Calyx 8-partecL 

 ( !orolla none. Stamens 3. Fertile flowers solitary, enclosed in a tubular spathe, 



and borne On a very lout: and mostly spiral scape. Sepals and small petal- .'!, 



united and coherent with t1 "' cylindrical 1-celled many-ovuled ovary. Stigmas 

 3, each 2-lobed. Seeds numerous, fixed t" three parietal placenta'. — Aquatic 

 berbfl, with creeping stems, and elongated strap-shaped leaves. Fertili 



I mostly as in Auaeliari-. 



