ALISMACEAE. 



Ovate-leaved Sagittaria, 



13. Sagittaria platyphylla (Engelm.) J. G. Smith. 



(Fig. 205.) 



Sagittaria graminea var. platyphylla Engelm. in A, 

 Gray, Man. Ed. 5, 494. 1867. 



Sagittaria platyphylla J. G. Smith, Ann. Rep. Mo. 

 Bot. Card. 6 : 55. pi. 26. 1894. 



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, 

 2'-6 / long ; bracts broadly ovate, acute, connate at 

 the base, 2"-A," long ; flowers S"-!^' broad ; fer- 

 tile pedicels stout, divergent in flower, reflexed in 



\ 



rather longer than the anthers ; achene obliquely 

 obovate, winged on both margins, the dorsal mar- 

 gin somewhat crested, the sides with a sharp wing- 

 like ridge. 



In swamps and shallow water, southern Missouri to- 

 Mississippi and Texas. Phyllodia, when present, 

 oblong or oblanceolate. July-Sept. 



14. Sagittaria subulata (I,.) Buchenau. Subulate Sagittaria. (Fig. 206.) 



Alisma subulata L. Sp. PI. 343. 1753. 

 Sagittaria pusilla NutL Gen. 2 : 213. 1818. 

 Sagittaria subulata Buchenau, Abh. Nat. Ver. Bremen, 

 3:490. 1871. 



Monoecious or rarely dioecious, scape very slen- 

 der, 2 / -6 / high, few-flowered, about equalling the 

 leaves. Leaves all reduced to rigid phyllodia or 

 sometimes bearing linear or linear-lanceolate 

 blades, i'-\% f long; bracts united to the apex or 

 becoming partly separated ; flowers 5 // -8 // 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 \" long, obovate, narrowly winged, 

 with 2 or 3 crests on each side, the wings and crests 

 sometimes crenate ; beak short. 



In tide-water mud, southern New York and Penn- 

 sylvania to Florida and Alabama. July-Sept. 



Sagittaria subulata gracillima (S. Wats.) J. G. Smith, Mem. Torr. Club, 5 : 26. 1894. 

 Sagittaria natans var. (1) gracillima S. Wats, in A. Gray, Man. Ed. 6, 556. 1890. 



Submerged ; leaves 2-4 long, bladeless or bearing small 3-nerved lanceolate blades, i'-2' 

 long, 3" -4" wide ; scape simple, terete or compressed, about as long as the leaves ; flowers few, 8"- 

 10" broad. Eastern Massachusetts and Rhode Island. Perhaps a distinct species. Fruit not seen. 



Family 6. VALLISNERIACEAE Dumort. Anal. Fam. 54. 1829. 



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 monadelphous. Anthers 2 -celled. Ovary 

 i -celled with 3 parietal placentae or 6-9-celled. Styles 3-9, with entire or 

 2 -cleft stigmas. Ovules anatropous 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 Florida. 

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



Acaulescent ; stoluniferous ; leaves grass-like, elongated. 2. Vallisneria. 



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



