ELODEACEAE 47 



Flowers monoecious or dioecious or rarely perfect, from spathes. Perianth 

 double, or the corolla wanting. Androeeium of 1-12 stamens. Gynoecium 3-15- 

 earpellary. Ovary inferior. Fruit capsular or baccate. 



Gynoecium 3-carpellarv, or rarely 2-, 4- or 5-carpellary: ovary 1-celled, with 3, or rarely with 2, 



4 or 5 parietal placentae: stigmas usually 3. Fam. 1. Ei.odeacf.ae. 



Gynoceium 6-9-carpellary: ovary 6-9-celled: stigmas 6-9. Fam. 2. Hvdrocharitaceae. 



Family 1. ELODEACEAE Dumort. Tape-grass Family. 



Plants with leafy stems, or leaves basal, often greatly elongated. Gynoe- 

 cium 2-5-earpellary, the ovary 1-celled. 



Staminate flowers with 1-3 stamens: plants with horizontal rootstocks. 



Leaves opposite on short horizontal stems; blades broad, more or less petioled: stigmas filiform: 



pollen filiform: marine plants. 1. Halophila. 



Leaves spiral, but in a basal cluster; blades linear, without petioles: stigmas 



short and broad: pollen spheroidal: fresh water plants. 2. Vallisneria. 



Staminate flowers with 9 stamens: fresh water plants with floating stems and 



whorled leaves. 3. Philotria. 



1. HALOPHILA Thouars. 

 Marine herbs. Leaves opposite or whorled. Flowers dioecious, the staminate 

 pedicelled, the pistillate sessile in the spathes. Fruit included in the spathe. 



1. Halophila EngelmAnnli Aschers. Leaf -blades linear, oblong or oblanceolate, 

 1-3 cm. long, sharply serrulate, 3-nerved, sessile: pistillate flowers flask-shaped. 

 In bays, coves and creeks, southern peninsular Florida. 



2. VALLISNERLA L. 



Fresh-water herbs. Leaves basal, with greatly elongated ribbon-like blades. 



Flowers dioecious, the staminate numerous, crowded on a spadix, the pistillate few, 



each solitary at the end of an elongated spiral scape. Fruit subtended by the spathe. 



Eel-grass. Tape-grass. 



Stigmas cleft for less than half their length: sepals of the pistillate flowers 2-3 mm. long. 



1. V. spiralis. 

 Stigmas cleft nearly to the base: sepals of the pistillate flowers 5-6 mm. long. 2. V. Americana. 



1. Vallisneria spiralis L. Leaf -blades thin, 3-8 mm. wide, usually denticulate, 



especially near the apex: peduncles of the pistillate flowers 3-6 dm. long, spirally 



twisted at maturity: spathe close-fitting, 1-1.5 cm. long: hypanthium 1-2 cm. long 



during anthesis: petals minute. 



In still or flowing water, Nova Scotia to South Dakota, North Carolina and Indiana. 

 Also in Europe and Asia. Summer and fall. 



2. Vallisneria Americana Michx. Leaf -blades thickish, 6-20 mm. wide, often 

 denticulate: peduncles of the pistillate flowers 5-10 dm. long or more, curved at 

 maturity, but scarcely spiral: spathe loose, 2-2.5 cm. long: hypanthium 2.5-3 cm. 

 long during anthesis: petals less than J as long as the sepals. 



In rivers and creeks. Gulf States, Florida to Louisiana. All year. 



3. PHILOTRIA Eaf. 



Fresh water herbs. Leaves cauline, opposite or whorled. Flowers dioecious, 

 polygamous or perfect, the staminate with 9 stamens, the perfect with 3-6 stamens, 

 the pistillate slender pedicelled. Fruit subtended by the spathe. Spring and summer. 

 Water-weed. 



Spathes of the staminate flowers sessile. 



Leaf-blades oblong to linear-oblong, 2-3 mm. wide: spathe of the staminate flowers 5-6 mm. long: 



anthers 2-2.5 mm. long. 1. P. Nuttallii. 



Leaf-blades linear 1.5 mm. wide or less: spathe of the staminate-flowers 2-4 

 mm. long: anthers about 1 mm. long. 

 Leaves 1 cm. long or more: sepals and petals 1.5-2 mm. long. 2. P. angustifoUa. 



Leaves less than 1 cm. long: sepals and petals 1-1.5 mm. long. 3. P. minor. 



Spathes of the staminate flowers peduncled. 4. P. linearis. 



1. Philotria Nuttdllii (Planch.) Eydb. Stems stout, mostly 3-10 dm. long: 

 leaf -blades oblong to lanceolate-oblong, 0.5-1 cm. long, acute, finely serrulate: spathe 

 of the staminate flowers ovoid: sepals and petals of the staminate flowers oblong, 

 2.5-3 mm. long: pistillate flowers with a hypanthium 5-15 cm. long and elliptic sepals 

 and petals 1.5 mm. long. 



In ponds and slow streams, New York to Virginia and Tennessee. 



