FLORA OF WORCESTER COUNTY. 55 



ACORUS, L. Sweet Flag. 



Calamus, L. Moist grounds, not rare. 



LEMNACE^E. 



LEMNA, L. Duckweed. 



minor, L. Stagnant waters, common. 



ALISMACE^:. 



ALISMA, L. Water- PI an tain. 



Plantago, L. Shallow water, common. 



SAGITTARIA, L. Arrow-head. 



variabilis, Engelm. In water or wet places. Common, 

 var. *obtusa. G. E. Stone. 



11 " " *angustifolia. " " " 



" " " *diversifolia. Princeton. 



W. W. B. &J. F. C. 



" " " gracilis, Engelm. G. E. Stone. 



graminea, Michx. " " " 



NAIADACE^E. 



POTAMOGETON, Tourn. Pondweed. (By the late Rev. Thos. 



Morong.) 

 natans, L. Very common. 



" " var. *prolixus, Koch. 



Oakesianus, Robbins. Uxbridge. 



Pennsylvanicus, Cham. Common in streams and ponds. 

 Vaseyi, Robbins. Lake Quinsigamond. 



Spirillus, Tuckerm. Common, 



hybridus, Michx. " 



fluitans, Roth. Worcester. Miss E. W. Sargent. 



