1919] Flora of the Boston District,—— XXX. 81 
RUTACEAE. 
PTELEA. 
P. TRIFOLIATA L. Waste places; Medford, Somerville, Boston, 
Roxbury, Dorchester, Dedham, Hingham, Newton, Wellesley. In- 
troduced from further south. 
ZANTHOXYLUM. 
Z. americanum Mill. Roadsides and old places, north and west 
of Boston. Probably introduced at most if not all stations. 
SIMARUBACEAE. 
AILANTHUS. 
A. GLANDULOSA Desf. Persistent and spreading, occasional. 
POLYGALACEAE. 
POLYGALA. 
P. cruciata L. Meadows and swamps; not reported from western 
towns, but occasional throughout the towns nearer the coast. 
P. Nuttalli T. & G. Old spur track, Sharon (E. F. Williams, 
Sept. 10, 1899. Specimens in herb. Gray and N. E. Botanical Club). 
P. paucifolia Willd. Woods and open places; unevenly dis- 
tributed but abundant, especially in southwestern towns. White 
form, forma alba Wheelock (Mem. Torr. Bot. Club. ii. 142, 1891) 
at Concord (Dame & Collins, Fl. Middlesex Co. 23, 1888; A. W. 
Hosmer, RHopona i. 173, 1899); violet form at Sudbury (A. W. 
Hosmer, Ruopona i. 173, 223, 1899). 
P. polygama Walt. Dry sandy and rocky soil; common except 
in northern Middlesex Co. 
