1909] Flora of the Boston District, — V. 207 
P. hybridus Michx. Still water, many stations in northern half of 
district, also occurring in Pembroke. Collected in Roxbury, “near 
Morlands,” Aug. 10-15, 1820; in Peabody by J. L. Russell, August, 
1854; and in Mystic Pond by Wm. Boott, Aug. 15, 1858. 
P. lateralis Morong. Charles River, Dedham (Wm. Boott and 
E. & C. E. Faxon, July 13, 1879; T. Morong, July 16, 1880; E. & C. 
E. Faxon and T. Morong, Aug. 2, 1880). 
P. lucens L. Fresh Pond, Cambridge (several collectors between 
1865 and 1886); Wenham Pond, Wenham (J. W. Robbins, no date; 
Wm. Boott, Sept. 20, 1867); Pleasant Pond, Wenham (J. Robinson, 
Aug. 13, 1875); Winchester (L. L. Dame, according to Dame & 
Collins, Fl. Middlesex Co., 100. 1888). 
P. mysticus Morong. Mystic Pond (T. Morong, E. & C. E. Faxon 
and Wm. Boott, various collections between 1865 and 1881); Wenham 
Pond, Wenham (E. & C. E. Faxon, Sept. 13, 1880 and Sept. 5, 1882). 
P. natans L. Ponds and slow streams; many stations, running as 
far south as Canton. 
X P. nitens Weber. Wenham Pond, North Beverly (E. & C. E. 
Faxon, Sept. 13, 1880, and Sept. 5, 1882; T. Morong & W. Deane, 
Sept. 8, 1886). 
P. Oakesianus Robbins. Ponds; Beverly, Dedham, Lynn, Natick, 
Stoneham, Woburn. Mystic Pond, Medford (Wm. Boott, according 
to Dame & Collins, Fl. Middlesex Co., 99. 1888). 
P. obtusifolius Mertens & Koch. Ponds and streams; Newbury, 
Wenham and Natick. 
P. praelongus Wulf. Fresh Pond, Cambridge (various collectors 
between 1865 and 1881); Pleasant Pond, Wenham, 1875 and 1880. 
P. pulcher 'l'uckerm. Ponds, streams and ditches; scattered sta- 
tions from all parts of district except the northwest and south. 
P. pusillus L. Ponds and streams; frequent, but no records from 
extreme northern and southern portions. 
P. pusillus L., var. polyphyllus Morong. Foster’s Pond, Andover 
(A. S. Pease, Sept. 11, 1903); Fresh Pond, Cambridge (E. & C. E. 
Faxon, July 22 & 23, 1880); shallow muddy pool, South Natick (T. 
Morong, Aug. 29, 1879); Spot Pond, Stoneham, (Wm. Boott, Aug. 20, 
1865). 
P. pusillus L., var. Sturrockii Benn. Woburn Brook (Wm. Boott, 
Aug. 25, 1867); Lake Cochichewick, North Andover (A. S. Pease, 
Sept. 24, 1903). 
