4 ZANNICHELLIACEAE. 



Ovary 1, stipitate, 1-2-celled. Ovules anatropous. Styles as many as the 

 cells of the ovary. Mingled among the stamens and pistils are bristly 

 hairs, and among the pistillate flowers many sterile flowers with clavate 

 tips. Fruit nut-like. Endosperm copious. The family comprises only the 

 following genus : 



1. TYPHA L. Sp. PI. 971. 1753. 



Characters of the family. [Name ancient.] About 10 species, widely dis- 

 tributed in temperate and tropical regions. Type species: Typha latifolia L. 



* 1. Typha angustifolia L. Sp. PI. 971. 1753. 



Typha domingensis Pers. Syn. PI. 2: 532. 1807. 



Typha angustifolia domingensis Griseb. Fl. Br. W. I. 512. 1864. 



Stems slender, 1.5-3.5 m. high. Leaves narrowly linear, 3-20 mm. wide, 

 erect, often as long as the stem ; spikes light brown, the staminate and pistil- 

 late portions usually separated, the two together sometimes 0.5 m. long, the pis- 

 tillate, when mature, 6-16 mm. in diameter, and provided with bractlets; stig- 

 mas linear or linear-oblong; pollen-grains simple; fruit not furrowed, not 

 bursting in water; outer coat of the seed not separable. 



In fresh water or slightly brackish marshes, Great Bahama, Abaco, New Provi- 

 dence, Andros, Eleuthera, Watling's Island : Bermuda : Jamaica ; Cuba to Tortola 

 and Trinidad : southern United States to Patagonia ; Europe ; Asia. Referred by 

 Dolley to Typha latifolia L. Cat-tail. Slag. 



Order 2. NAIAD ALES. 



Aquatic or marsh herbs, the leaves various. Flowers perfect, monoe- 

 cious or dioecious. Perianth rudimentary, or wanting. Parts of the flower 

 mostly unequal in number. Carpels 1 or more, distinct and separate or 

 united; endosperm none, or very little. 



Carpels distinct. Fam. 1. Zannichelliaceae. 



Carpels 2, united, or 1 only. Fam. 2. Cymodoceaceae. 



Family 1. ZANNICHELLIACEAE Dumort. 



Pondweed Family. 



Perennial plants, the foliage mostly submerged. Leaves very narrow 

 or broad. Flowers monoecious or perfect, small, and inconspicuous. 

 Perianth present or none. Stamens 1-4, with extrorse anthers. Carpels 

 1-seeded. Fruit drupe-like. Endosperm none. Four genera and sixty 

 or more species, mostly inhabiting fresh water. 



Perianth of 4 segments. 1. Potamogeton. 



Perianth wanting. 2. Ruppia. 



1. POTAMOGETON L. Sp. PI. 126. 1753. 



Leaves alternate or the uppermost opposite, often of 2 kinds, submerged 

 and floating, the submerged mostly linear, the floating coriaceous, lanceolate, 

 ovate or oval. Spathes stipular, often ligulate, free or connate with the base 

 of the leaf or petiole, enclosing the young buds and usually soon perishing after 

 expanding. Peduncles axillary, usually emersed. Flowers small, spicate, green 

 or red. Perianth-segments 4, short-clawed, concave, valvate. Stamens 4, 



