VA LLTSNERIA CEA E. 59 



obovate, the dorsal margin with a broad crenate wing, the ventral straight-winged, 

 each side bearing 2 crenate crests, the beak short, oblique. In shallow water, la. 

 and Minn. Phyllodes are commonly developed from the nodes of the rootstock. 

 July-Aug. 



13. Sagittaria graminea Michx. Grass-leaved Sagittaria. (I. F. f. 

 204.) Monoecious or dioecious; glabrous; scape simple, erect, 0.1-0.6 m. tall. 

 Leaves long-petioled, the blades linear, lanceolate or elliptic, acute at both ends. 

 5-15 cm. long, 1-6 cm. wide, 3-5-nerved, with nerves distinct to the base, or some 

 of them occasionally reduced to flattened phyllodes; bracts ovate, acute, 3-6 mm. 

 long, much shorter than the slender or filiform fruiting pedicels, connate to the 

 middle or beyond; flowers 8- 1 2 mm. broad; stamens about 18; filaments dilated, 

 pubescent, longer than or equalling the anthers; achene obovate, 1-2 mm. long, 

 slightly wing-crested on the margins and ribbed on the sides, the beak very short. 

 In mud or shallow water, Newf. to Ont. and S. Dak. , south to Fla. and Tex. 

 Early leaves often purplish. July-Sept. 



14. Sagittaria platyphyUla (Engelm.) J. G. Smith. Ovate-leaved Sagit- 

 taria. (I. F. f. 205.) Monoecious; glabrous; scape erect, simple, rather weak, 

 mostly shorter than the leaves. Leaves rigid, the blades ovate, ovate-lanceolate 

 or ovate-elliptic, short-acuminate or acute at the apex, rounded, gradually 

 narrowed or rarely cordate or hastate at the base, seemingly pinnately-veined, 5— 15 

 cm. long; bracts broadly ovate, acute, connate at the base, 4-8 mm. long; flowers 

 1.6-3 cm. broad; fertile pedicels stout, divergent in flower, reflexed in fruit, 1-6 

 cm. long; filaments dilated, pubescent, rather longer than the anthers; achene 

 obliquely obovate, winged on both margins, the dorsal margins somewhat crested, 

 the sides with a sharp wing-like ridge. In swamps and shallow water, S. Mo. to 

 Miss, and Tex. Phyllodes, when present, oblong or oblanceolate. July-Sept. 



15. Sagittaria subulata (L.) Buchenau. Subulate Sagittaria. (I. F. f. 

 206.) Monoecious or rarely dioecious; scape very slender, 5— 15 cm. high, few- 

 flowered, about equalling the leaves. Leaves all reduced to rigid phyllodes or 

 sometimes bearing linear or linear-lanceolate blades 2-4 cm. long; bracts united 

 to the apex or becoming partly separated; flowers 1 -1. 6 cm. broad; fertile pedicels 

 reflexed and much longer than the bracts in fruit; stamens about 8; filaments 

 about equalling the anthers, dilated, glabrous ; achenes rather less than 2 mm. long, 

 obovate, narrowly winged, with two or three crests on each side, the wings and 

 crests sometimes crenate; beak short. In tide- water mud, S. N. Y. and Penn. to 

 Fla. and Ala. July-Sept. (S. pusilla Nutt.) 



Sagittaria subulata gracillima (S. Wats.) J. G. Smith. Submerged; leaveso.6-1.3 dm. 

 long, bladeless or bearing small 3-nerved lanceolate blades 2-5 cm. long, 6-8 mm. wide ; 

 scape simple, terete or compressed, about as long as the leaves; flowers few, 1.6-2 cm. 

 broad. E. Mass. and R. I. Perhaps a distinct species. Fruit not seen. 



Family 6. VALLISNERIACEAE Dumort. 



Tape-Grass Family. 



Submerged or floating aquatic herbs, the leaves various. Flowers 

 regular, mostly dioecious, appearing from an involucre or spathe of 1-3 

 bracts or leaves. Perianth 3-6-parted, the segments either all petaloid 

 or the 3 outer ones small and herbaceous, the tube adherent to the ovary 

 at its base in the pistillate flowers. Stamens 3-12, distinct or monadel- 

 phous. Anthers 2-celled. Ovary 1 -celled with 3 parietal placentae or 

 6-9-celled. Styles 3-9, with entire or 2-cleft stigmas. Ovules anatro- 

 pous or orthotropous. Fruit ripening under water, indehiscent. Seeds 

 numerous, without endosperm. About 14 genera and 40 species of wide 

 distribution in warm and temperate regions. Besides the following, 

 another genus, Halophila, occurs on the coast of Fla. 



Stem branched ; leaves whorled or opposite. 1. Philotria. 



Acaulesce'.u ; stoloniferous ; leaves grass-like, elongated. 2. Vallisneria. 



Stem stoloniferous ; leaves broad, rounded, cordate, petioled. 3. Limnobium. 



