34 



§ 8 orientale L. Princes Feather. 



9 persicaria L. Heart's Ease. Ladies' Thumb'. 



10 punctatum Ell. Biting Knot-weed. 



11 sagittatum L. Prickly Knot-weed. 



12 scandens L. Climbing Buck Wheat. 



13 tenue Mx. Slender Knot Grass. 



14 virginianum L. 



15 viviparum L. White Hills. 



302 Polypogon Desfout. 



1 glomeratus W. racemosus JVutt. 



303 Pontederia L. 



1 angustifolio Ph. cordata p angusti Torrey. Leverett. 



2 cordata L. Pickerel Weed. 



304 Populus L. 



1 angulata L. Balm of Gilead. Cotton Wood. 



2 halsamifera Wang. Balsam Poplar. 

 <§ 3 dilatata L. Lombardy Poplar. 



4 grandidentata Mx. Poplar. 



5 tremuloides Mx. White Poplar. Aspen. 



305 Portulacca L. 



1 oleracea L. Purslane. 



306 Potamogeton L. Pond Weed. 



1 compressum W. 



2 fluitans L. 



3 gramineum Mx. 



4 heterophyllum Schreb. 



5 natans L. 



6 pectinatum Sm. Piitsfield. 

 1 perforatum L. 



8 setaceum Ph. diversifolium Barton. 



307 Potentilla L. 



1 argentea L. Silver Five Finger. 



2 canadensis L. Five Finger. 



3 confertiflora Torrey. Geum agrimonoides Ph. Bootia syl- 

 vestris Bigelow. 



4 fruticosa L. Stockbridge. 



5 norwegicaL. Cinquefoil. 



6 palustris Scop. N. Haven. Marsh Five Finger. Comarum 

 palusire L. 



