10 ELODIACEAE 



b. I,eaf-blades entire, rarely cordate. 

 Filaments slender : leaf -blades seemingly pinnate! j' veined. 



4. 5. rigida. 

 Filaments dilated : leaf-blades with veins distinct to the base. 



5. 5". graminea. 

 B. Pedicels of the pistillate flowers stout, reflexed at maturity. 



6. 5'. snbulata. 



1. Sagittaria longirostra (Micheli) J. G. Smith. Long-beaked 

 Arrow-head. (Man. p. 57 ; I. V.f. 193.) In swamps and along ponds. 

 N.J. and Pa. to Ala. — Pennsylvania : Lancaster; Delaware. 



2. Sagittaria Engelmanniana J. G. Smith. Engelmann's Arrow- 

 head. (Man. p. 57 ; L V.f. 194.) In shallow water, Mass. to Pa. and 

 Del. — Pennsylvauia : Monroe, Tobyhanna; Northampton ; Luzerne ; 

 Philadelphia. 



3. Sagittaria latifolia Willd. Broad-leaved Arrow-head. (Man. 

 p. 57 ; I. F.y". /pj. ) In low grounds and shallow water, nearly through- 

 out N, A. — Pennsylvania : Monroe ; Northampton ; Delaware ; 

 Chester ; Lancaster ; Huntingdon ; Franklin ; Erie ; Alle- 

 gheny. Common. 



3a. S. latifolia pubescens (Muhl. ) J. G. Smith. (Man. p. 57.) — 

 Northampton, Seidersville. 



4. Sagittaria rigida Pursh. Sessile-fruiting Arrow-head. (Man. 

 p. 58 ; I. F.y". 201.^ In shallow water and swamps, Quebec to Minn., N. 

 J., Tenn. andNeb. — Pennsylvania: Northampton; Bucks; Philadel- 

 phia ; Lancaster ; Dauphin, Harrisburg ; Bradford. 



5. Sagittaria graminea Michx. Grass-leaved Sagittaria. (Man. 

 p. 59 ; I. V.f. 20^.) In shallow water or mud, Newf. to S. Dak., Fla. and 

 Tex. — Pennsylvauia : Pike, Twelve Mile Pond; Northampton; Del- 

 aware ; Berks ; Erie. 



6. Sagittaria subulata (L. ) Buchenau. Subulate Sagittaria. 

 (Man. p. 59: I. F. /. 206.) In tidewater mud, N. Y. to Pa., Fla. and 

 Ala. — Pennsylvania: Philadelphia; Delaware. 



6a. S. subulata gracillima (S. Wats.) J. G. Smith. (Man. p. 59.) — 

 Bucks, Bristol. 



Order 4. HYDROCHARITALES. 



Family i. ELODIACEAE Dumort. Tape-grass Family. 

 Staminate flowers with 9 stamens. i. Philotria. 



Staminate flowers with 1-3 stamens. 2. Vallisneria. 



1. PHILOTRIA Raf. 



Leaf-blades oblongr, elliptic or ovate-oblong. i. P. Canadensis. 



Leaf -blades narrowly linear. 2. P. angjislifolia. 



1. Philotria Canadensis (Michx.) Britton. Water-weed. Ditch- 

 MOSS. (Man. p. 60.) In ponds aud streams, nearly throughout N. A. 

 — Pennsylvania: Northampton; Bucks; Philadelphia; Dela- 

 ware ; Chester ; Lancaster ; Lycoming ; Huntingdon ; Erie. 



