MIDDLESEX FLORA. 39 



MELASTOMACEy^. MELASTOMA FAMILY. 



RHEXIA, L. 



R. Virginica, L. MEADOW BEAUTY. 

 Not uncommon. July-Aug. 



LYTHRACE>. LOOSESTRIFE FAMILY. 



AMMANNIA, HOUSTON. 



A. humilis, Michx. 

 Winchester, Winter Pond (Dr. C. W. Swan). Rare. July-Sept. 



LYTHRUM, L. 



L. Hyssopifolia, L. LOOSESTRIFE. 



Maiden (W. H. Manning; Mrs. C. E. Pease); Medford (Wm. 



Boott) ; Arlington (F. S. Collins). Rare. July. 

 L. alatum, Pursh. 



Chelmsford (Miss C. E. Preston). Probably introduced in western 



wool. June-Aug. 

 L. Salicaria, L. SPIKED LOOSESTRIFE. 



Chelmsford (W. H. Manning) ; Ashland, rather common (Rev. 



Thos. Morong) ; Framingham (Rev. J. H. Temple). Rare north- 



ward. July-Aug. Possibly introduced. 

 L. acutangulum, Lag. 



Lowell, a single specimen on the sandy bank of the Merrimac (Dr. 



C. W. Swan). 



" Herbaceous, leaves alternate, linear, lanceolate; pedicels short, 



erect even in fruit; bractlets acute, very small; petals 6, oblong- 



ovate ; stamens 12." DC. Prodr. Ill, 82. 



, Commerson, Juss. 



N. verticillata, HBK. SWAMP LOOSESTRIFE. 

 Common, especially in the northern part of the county. July-Aug. 



CACTACE^E, CACTUS FAMILY. 



OPUNTIA, Tourn. 

 *O. VULGARIS, Haworth. PRICKLY PEAR. 



N. Reading, bank of the Ipswich river (J. Robinson, Flora of 

 Essex). June-July. Int. from farther south. 



