90 MIDDLESEX FLOKA. 



C. demersum, L., var. echinatum. Gray. 

 Cambridge, specimen in herb. B. S. N. H. 



CALLITRICHACEy^. WATEE-STAEWOKT FAMILY. 



Calliteiche, L. 



G. verna, L. Watee Staewoet. 



Common. May-July. 

 C. heterophylla, Pursh. 



Ashland (Rev. Thos. Morong) ; Maiden (H. A. Young) ; Spot 



Pond (Wm. Boott). May-July. 



PODOSTEMACEv^. RIVER-WEED FAMILY. 



PODOSTEMON, Michx. 



p. ceratophyllus, Michx. Rivee-webd. 

 In'the Charles River, So. Natiok (Edwin Faxon). July-Sept. 



EUPHORBIACE.^. SPURGE FAMILY. 



EUPHOEBIA, L. 



E. maculata, L. 



Very common. July-Sept. 

 E. hypericifolia, L. 



Lowell (Dr. C. W. Swan) ; Concord (Minot Pratt) ; Pramingham 



(Rev. J. H. Temple). Rare. July-Sept. 

 -B. coroUata, L. Floweeing Sptjege. 



Lowell, " dump " (Dr.' C. W. Swan). July-Sept. Adv. from the 



West. 

 £\ Esula, L. 



Somerville (C. E. Perkins) ; Waltham List. Rare. June. Adv. 



from Eu. 

 E. Cypaeissias, L. Ctpeess Sptjege. 



Common. May-June. Nat. from Eu. 



ACALTPHA, L. • 



A. Virginica, L. Theee-seedbd Meecuet. 

 Common. July-Sept. 



