102 MIDDLESEX FLORA. 



SAGITTARIA, L. 



S. variabilis, Engelm. ARROW-HEAD. 



Very common; including vars. obtusa and latifolia, Engelm., 



Maiden (H. L. Moody) ; var. hastata, Engelm., Cambridge (G. 



E. Davenport); var. diversifolia, Engelm., Lowell (W. H. 



Manning) ; and var. angustifolia, Lowell (L. L. Dame). June- 



Aug. 

 S. calycina, Engelm. 



Medford (Wm. Boott, specimen in herb. of). July. 

 S. graminea, Michx. 



Cambridge and Arlington (C. E. Perkins) ; Framingham and 



Natick (Rev. Thos. Morong) ; Medford (W. H. Manning). Aug. 

 S. graminea, Michx., var. fluitans, Engelm. 



So. Natick (Rev. Thos. Morong; specimen in herb. of). Aug. 

 S. natans, Michx. 



Westford (C. E. Perkins) ; Littleton (W. H. Manning). 



HYDROCHARIDACEy^E. FROG'S-BIT FAMILY. 



ANACHARIS, Rich. 

 A. Canadensis, Planch. WATER-WEED. 



Somerville (Warner Bailey) ; Arlington (Wm. Boott) ; Fresh Pond, 

 Cambridge (Rev. Thos. Morong). July. 



VALLISNERIA, Mich. 



V. spiralis, L. TAPE-GRASS. EEL-GRASS. 

 Common. July-Aug. 



ORCHIDACE^E. ORCHID FAMILY. 



ORCHIS, L. 



*O. spectabilis, L. SHOWY ORCHIS. 



Cambridge (T. W. Harris in Hovey's Mag., VI., 245). Concord, in- 

 troduced from Vermont by Minot Pratt. May. Very rare. 



HABENARIA, Willd., R. Br. 



H. tridentata, Hook. 

 Common. June-Aug. 



H. virescens, Spreng. 

 Not uncommon. June-July. 



H. dilatata, Gray. 



Lexington (Baldwin's Orchids of N. E.) ; Reading and Stoneham 

 (Wm. Boott, specimen in herb. of). The Concord plant was intro- 

 duced by Minot Pratt. June-July. 



