440 htdeocharidacejE. (frog's-bit family.) 



7-9; OTaries short-pointed (ripe fmit not seen). (Alisma subulata, Pursh.) — 

 Low shoies, near Philadelphia, &c. — Apparently distinct from dwarf forms of 

 the last; but needs further investigation. 



S. nAtans, Mic'hx., apparently the only remaining good species in the Unit- 

 ed States, is only found farther south. 



Order 117. HYDROCHARIDACE^. (Frog's-bit Fam.) 



Aquatic herbs, with dicecious or polygamous regular flowers on scape-like 

 peduncles from a spalhe, and simple or double floral envelopes, which in the 

 fertile flowers are united into a tube and coherent with the 1 — 9-celled ovary. 

 Stamens 3-12, distinct or monadelphous : anthers 2-celled. Stigmas 3 or 

 6. Fruit ripening under water, indehisoent, many-seeded. Seeds Jisceud- 

 ing, without albumen : embryo straight. 



Synopsis. 



Tbibe I. STRATIOTIDEJE. Oyary 6 - 9-ceUcd : stigmas 6 - 9. 



1. LIMNOBITJM Filaments unequally united into a solid column in the starainate flowers • 



anthers 6-12, linear. 



Tkibb II. VALIilSlVERIX:^. OTary 1-celled, with 3 parietal plaoentse : stigmas 3. 



2. ANACHARIS. Stem leafy. Tube of the perianth of the fertile flowers long and thread- 



form ; its lobes 6. 

 8. TALHSNERIA. Stemless, Tube of the perianth not prolonged beyond the elongated 

 ovary ; its lobes 3. 



1. LiinHVOBIUM, Richard. Amekican Fkog's-bit. 



Flowers dicecious, (or monoecious t) from sessile or somewhat pcduncled 

 spathee ; the sterile spathe 1-leaved, producing about 3 long-pedicelled flowers ; 

 the fertile 2-leaved, with a single short-pedicelled flower. Calyx 3-paited or 

 cleft ; sepals oblong-oval. Petals 3, oblong-linear. Filaments entirely united 

 in a central solid column, bearing 6-12 linear anthers at unequal heights : tlicre 

 are 3-6 awl-shaped rudiments of stamens in the fertile flowers. Ovary 6-9- 

 celled, with as many placentae in the axis, forming an ovoid many-seeded berry 

 in fruit : stigmas as many as the cells, but 2-parted, awl-shaped (ovules orthotro- 

 pous, Tmr.). — A stemless perennial herb, floating in stagnant water, prolif- 

 erous by runners, with long-petioled and round-heart-shaped leaves, which are 

 spongy-reticulated and purplish underneath; rootlets slender, hairy. Sterile 

 flowers rallicr small ; the fertile larger : peduncle nodding in fi-uit. Petals 

 white ■? (Name from Xi/ivoPios, living in pools.) 



1. L.. Spun^a, Richard. (Hydrocharis, Bosc. H. cordifolia, iV»«.) — 

 Braddock's Bay (Monroe County, N. T.), Lake Ontario, Dr. Bradley, Dr. Sart- 

 wdl. (Otherwise only in the Southern States.) Aug. — Leaves l'-2' long, 

 faintly 5-nerved. Peduncle of the sterile flower about 3' long, tlircad-like ; of 

 the fertile, only 1', stout. 



