26 ELODEACEAE 
20. S. viscosa C. Mohr. Leaf-blades 20—35 em. long, the seg e broadly 
ovate, the basal lobes shorter, acute or acuminate: scape 5-8 dm , with few 
flower-whorls: braets obtuse: fruit-heads not seen.—Muddy places yee marshes 
Coastal Plain, N Fla. and S Ala. 
21. S. "ipe pasce J. G. Smith. Leaf-blades oe 25 em. tong the 
Pp pe broadly ovate, the basal ones as lon ng but narrower: scape 4—8 
ith few oe ower- -whorls: braets pice fruit-heads 12-18 mm. 
DUE pos P MIND achene 4 mm. long, with fa cial Bec the dorsal wing 
par tially erenate, the i: ak erect.—Pon "re and streams, Coastal Plain 
and rarely adj. provinces, Fla. to Ar k., Pa., and N. J. 
22. S. australis (J. G. Smith) Small. Leaf-blades 8-10 cm. long, the terminal 
lobe very broad, the basal lobes shorter, obtuse: scape 4—5 dm. La with 4—6 
flower-whorls: fruit- heads fully 10 mm. thick: achene 3-3.5 m . long, w with 
faeial wings, the dorsal wing undulate, the beak cud over the ‘crest.—Low 
grounds, Appalachian Plateau, N Ala 
23. S. montevidensis C. & S. Leaf-blades 1-5 dm. long, the basal lobes nar- 
rower and shorter than the ovate terminal one: scape very stout, about as tall as 
T a the pedicels relatively short: fruit-heads 15-30 mm. thick: achene 
2-3 mm. long, the slender beak oblique.—(GIANT-ARROWLEAF.)—Low grounds 
and ae Coastal Plain, Fla. to Ala. and N. C.; also Calif. Nat. of S. A. 
OrpER HYDROCHARITALES — HyprocHArRITAL ORDER 
Perennial aquatic herbs, with rootstocks. Leaves usually with blades. 
Flowers monoecious or dioecious, or rarely perfect, from spathes. Perianth 
double, or the corolla wanting. Androecium of 1-12 stamens. Gynoecium 
3-15-carpellary. Ovary inferior. Fruits capsular or baccate 
Gynoecium 3- i ci or rarely 2-, 4- or oin ovary 1-celled, with 3, or 
rarely with 2, 4 o parietal placentae: stigma 
ually Fam. 1. ELODEACEAE. 
Gynoecium 6-9 earpellary: ovary 6-9-celled : stigmas 
6-9. Fam. 2. HYDROCHARITACEAE. 
Famity d. HLODEACEAE — TAPE-GRASS FAMILY 
Plants with leafy stems, or leaves basal, often pl elongate. Gyno- 
ecium 2-5-carpellary, the ovary l- celled. —Com mpri s 6 genera and about 
24 species, widely distributed in warm region 
Staminate flower with 1-3 stamens: plant with horizontal rootstocks. 
eaves opposite on short horizontal stems ; ee broad, more or less petioled: 
stigmas filiform : pollen filiform : marine plan 1. HALOPHILA. 
Leaves spiral, but in a basal cluster; blade ieee without 
a petiole: stigmas short and broad: pollen spheroidal : 
fresh water plan 2. VALLISNERIA. 
Staminate flower with 9 stamens: fresh water plant with float- 
ing stems and whorled leaves. 3. PHILOTRIA. 
1. HALOPHILA Thouars. Marine submerged herbs, with short branches 
arising from the rootstock. Leaves opposite or whorled, the lower ones oft 
scale-like. Flowers dioecious or monoecious, the staminate pedicelled, the 
Pa sessile in the spathe, flask-shaped. Fruit short, s. in the 
athe.—About 6 species, mostly cireumtropieal.—SEA-GRASSES— The plants 
Rom on the sea-bottom, in shallow water, or at i depths when 
