ZANNICHELLIACEAE 5 



B. Pistillate spikes sessile : upper leaves not sac-like at the base nor scari- 

 ous-margined. 

 Pistillate spikes 10-16 mm. in diameter : staminate spikes 4-6. 



4. 5. simplex. 

 Pistillate spikes 4-10 mm. in diameter : staminate spikes 1-2. 



5. 5. minimum. 



1. Sparganium eurycarpum Engelm. Broad-fruiTed Bur-reed. 

 (Man. p. 39; I. F. y. ijS.) In marshes and along streams, Newf. to 

 Br. Col., N. C. , Mo. and Calif. — Pennsylvania: Northampton; Lan- 

 caster ; Delaware. 



2. Sparganium androcladum (Engelm.) Morong. Branching BuR- 

 REED. (Man. p. 39; I. F./. 139.) In swamps or shallow water, N. S. 

 to Br. Col., Fla. and L,a. — Pentisylvania : Northampton; Chester; 

 Lancaster ; Delaware ; Franklin ; Huntingdon ; Bucks ; Bed- 

 ford ; Erie ; Jefferson. 



2a. S.^aDdrocladum fluctruans Morong. (Man.Jp. 40.) — Monroe ; Sus- 

 quehanna ; Wayne ; Centre, Bear Meadows; Schuylkill ; Somer- 

 set ; Franklin. 



3. Sparganium Americanum Nutt. American Bur-reed. (Man. 

 p. 1038.) In low grounds or ponds, Ont. to Br. Col., Pa. and the Ind. 

 Terr. — Pennsylvania : Philadelphia. 



4. Sparganium simplex Huds. Simple-stemmed Bur-reed. (Man. 

 p. 40; I. F.y. /40.) Along streams and ponds, Newf. to Br. Col., Pa., 

 Mont, and Calif. — Pennsylvania : Susqueh.\nna ; Monroe ; Somerset. 



5. Sparganium minimum Fries. Small Bur-reed. (Man. p. 40; 

 I. F./. 14/.) In ponds and streams, N. B. to Man., Ore., N. J., Mich, 

 and Utah. — Pennsylvania : Tioga ; Erie, Presque Isle. 



Order 2. NAIADALES. 



Gynoecium of distinct carpels : stigmas disk-like or cup-like. 



Fam. I. ZANNICHELLIACEAE. 



Gynoecium of united carpels : stigmas 2-4, slender. 



Fam. 2. Naiadaceae. 



Family i. ZANNICHELLIACEAE Dumort. Pondweed Family. 

 Flowers monoecious : stamen i ; connective without an appendage : drupelets 



stipitate. i. Zannichellia . 



Flowers perfect : stamens 4 ; connectives with broad appendages : drupelets 



sessile. 2. Potamogeton. 



1. ZANNICHELLIA L- 



1. Zannichellia palustris L. Zannichellia. (Man. p. 50; I. F./. 

 178.) In fresh or brackish ponds, pools or ditches, nearly throughout 

 N. A. — Pennsylvania: Northampton; Philadelphia; Chester; 

 Luzerne. 



2. POTAMOGETON L. 

 A. Stipules axillary and free from the rest of the leaf. 



a. Plants with both submerged and floating leaves. 



