6 HYDEOCHAEITACEAE. 



1. S. lorata (Chapm.) Small. Leaf-blades floating, elliptic, oblong, or ovate- 

 oblong, 1.5-5 cm. long, or wanting, the phyllodia stout: scapes 1-10 dm. long 

 or more, with 1 or several flower-whorls: achenes numerous, about 2 mm. long. 

 — Streams. 



2. S. lancifolia L. Leaf-blades elliptic or nearly so to narrowly elliptic-lanceo- 

 late, 30-60 cm. long, mainly 5-9-nerved: pedicels of pistillate flowers relatively 

 long, their bracts of a lanceolate type: achenes 2.5-3 mm. long. — Everglades. — 

 F. K. {Bah., Cuba, Ant.) 



3. S. falcata Pursh. Leaf-blades narrowly elliptic, sometimes slightly broadest 

 above the middle, or nearly linear, 10-35 cm. long, mainly 3-5-nerved: pedicels 

 of the pistillate flowers relatively short, their bracts of an ovate type: achenes 

 about 2 mm. long. — Everglades. 



Order HYDROCHARITALES. 



Perennial aquatic herbs with rootstocks. Leaves usually with blades. 



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



double, or corolla wanting. Androecium of 1-12 stamens. Gynoeeium 



3-15-carpellar>'. Ovary inferior. Fruit capsular or baccate. 



Gynoeeium S-carpellary, or r.irely 2-, 4- or 5-carpellary : ovary 1-celled : stigmas 3. 



Fam. 1. Elodeaceae. 

 Gynoeeium 6-12-earpellary : ovary 6-12-celled : stig- 

 mas 6-12. Fam. 2. IIydrocharitaceae. 



Family 1. ELODEACEAE. Tape-grass Family. 



Plants with leafy stems, or leaves basal, often greatly elongate. 

 Gynoeeium 2-5-carpellary, the ovaiy 1-celled. 



Leaves with petioled dilated blades : stigmas filiform : pollen filiform : marine plants. 



1. Halophila. 

 Leaves greatly elongate phyllodes, without petioles : stigmas 



short and broad : pollen spheroid : fresh-water plants. 2. Vallisnekia. 



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. H. Engelmannii Aschers. Leaf-blades linear, oblong, or oblanceolate, 1-3 

 cm. long, sharply serrulate, 3-nerved, sessile: bracts lanceolate: hypanthium 

 flask-shaped, 8-9 mm. long; body ovoid; neck longer than the body: sepals 

 minute. — Bay Biscayne. — F. K. (Bali.). 



2. VALLISNEKIA [Mich.] L. Fresh-water herbs. Leaves basal, with 

 elongate, ribbon-like blades. Flowers dioecious, the staminate numierous, 

 crowded on a spadix, the pistillate few, each solitary at the end of an elongate 

 spiral scape. Fruit subtended by the spathe. 



1. V. americana Michx. Leaf-blades narrowly linear, 3-8 dm. long, 2 cm. 

 wide or less, often denticulate, obtuse: peduncles of the pistillate flowers 5-10 

 dm. long or more: spathe 2-2.5 cm. long: mature hypanthium about 1 dm. 

 long: sepals oval, 5-6 mm. long: petals about 2 mm. long: stigma-lobes 

 abruptly short-acuminate. — Everglades and streams. — Tape-orass. Eel-grass. 



Family 2. HYDROCHARITACEAE. Frog's-bit Family. 



Plants with leaves in cluslcrs on the rootstocks. Gynoeeium 6-12- 

 earpellai-y, the ovary (j-12-eelled. 



