^ 
1910] Flora of the Boston District,— VI. 5 
ARACEAE. 
ACORUS. 
A. Calamus L. Swamps and borders of still waters, common 
throughout. 
ARISAEMA. 
A. triphyllum (L.) Schott. Rich moist woods, common and 
abundant. 
CALLA. 
C. palustris L. Very wet muddy places. We have no records from 
the southeastern section, but the plant occurs sparingly throughout 
the rest of the district. 
PELTANDRA. 
P. virginica (L.) Kunth. Wet meadows and muddy shores, fre- 
quent throughout. 
SYMPLOCARPUS. 
8. foetidus (L.) Nutt. Wet woods and swamps; common and 
abundant throughout. 
LEMNACEAE. 
LEMNA. 
L. minor L. Still water, common in central part of the area. 
L. trisulca L. Fresh Pond, Cambridge (Wm. Boott, August, 1859; 
C. E. Perkins, July 17, 1879); Glacialis, Cambridge (J. Murdoch, 
Jr., May 7,1904); Lincoln (E. F. Williams, Sept. 5, 1902); “ Alewife 
Brook below bridge on the Powderhouse Road, Medford" (Wm. Boott, 
Nov. 3, 1867). 
L. valdiviana Philippi. Nooks in slow streams; Monatiquot Stream, 
Blue Hill Reservation; and Beaver Brook, Sharon. 
SPIRODELA. 
S. polyrhiza (L.) Schleid. Still water; frequent in northern half 
of district, but not reported from the southern towns. 
