1922] 



PFEIFFER MONOGRAPH OF THE ISOETACEAE 167 



N. Y. Bot. Gard. Herb.) ; Mystic Pond, mouth of Arling- 

 ton Brook, 2 June, 1867, Boott (Mo. Bot. Gard. Herb.); 

 along banks of Mystic Pond, 21 October, 1866, Boott (Mo. 

 Bot. Gard. Herb.) ; Mystic Pond, 14 and 30 July, 1864, Boott 

 (Gray Herb.) ; east side of Mystic Pond, 8 September, 1807. 

 Boott (Mo. Bot. Gard. Herb.); west side of Mystic Pond, 

 north of Brook, 12 July, 1868, Boott (Gray Herb.); south 

 side of Spy Pond, Arlington, 5 and 9 September, 1867, Boott 

 (Mo. Bot. Gard. Herb.); Spot Pond, 6 September, 1868, 

 Boott (N. Y. Bot. Gard. Herb.) ; Spot Pond, Stoneham, 23 

 July, 1867, Boott (Mo. Bot. Gard. Herb.) ; Spot Pond, 18 

 November, 1866, Boott (U. S. Nat. Herb.) ; Horn Pond, Wo- 

 burn, September, 1862, Mann (Gray Herb.) ; island in middle 

 of Horn Pond, 11 July, 1867, Boott (Mo. Bot. Gard. 

 Herb, and Gray Herb.) ; northwest side Horn Pond, 16 Sep- 

 tember, 1869, Boott (N. Y. Bot. Gard. Herb.) ; Fresh Pond, 

 17 September, 1867, Boott (Mo. Bot. Gard. Herb, and Gray 

 Herb.); Concord Brook, 20 August, 1866, Boott (Mo. Bot. 

 Gard. Herb.); Round Pond, Woburn, 1 October, 1874, 

 Davenport (N. Y. Bot. Gard. Herb.) ; Hammond's Pond, 

 Brookline, without date, C. E. Faxon (Mo. Bot. Gard. 

 Herb.); Round Pond, Woburn, without date, C. E. Faxon 

 (Mo. Bot. Gard. Herb.); Hammond's Pond, 1878, Farlow 

 (Mo. Bot. Gard. Herb.) ; Tofit Swamp Brook, Lexington, 17 

 July, 1867, Boott (Gray Herb, and N. Y. Bot. Gard. Herb.) ; 

 brook in Tofit Swamp, Lexington, 9 September, 1867, Boott 

 (Mo. Bot. Gard. Herb, and Gray Herb.); South Natick, 14 

 July, 1879, Morong (Mo. Bot. Gard. Herb.); "entirely sub- 

 merged in pool, South Natick", 13 August, 1883, Morong 

 (N. Y. Bot. Gard. Herb.); ponds, West Cambridge,:' 1861, 

 Boott (Mo. Bot. Gard. Herb.) ; Concord, in streams, Sep- 

 tember, 1863, Mann (Gray Herb.) ; Concord, 1 October. 

 1863, Mann (Mo. Bot. Gard. Herb.) ; Concord, without date, 

 Mann (Gray Herb.) ; small pond in Winchester (for- 

 merly Woburn), August, 1876, Morong 353 (U. S. Nat. 

 Herb.) ; small pond in Winchester, 22 August, 1876, Morong 

 (N. Y. Bot. Gard. Herb.) ; brooks, slow moving water, Mel- 

 rose, 8 July, 1875, Morong (N. Y. Bot. Gard. Herb.); in 

 running water, Melrose, September, 1876, Morong (IT. S. 

 Nat. Herb.) ; Sandbury River, Framingham, September, 



