1915] Flora of the Boston District,— XX. 171 
URTICA. 
U. pioica L. Waste places, rare; Boston, Roxbury, Dorchester, 
Concord, Watertown, Framingham; Hingham, according to Bouvé, 
Botany of Hingham, in History of Hingham, i. pt. 1, 124, 1893. 
U. gracilis Ait. Moist ground in waste places; common. 
U. Lyallii Wats. Moist ground in waste places; numerous reports 
from central and northern portions of the district. 
U. urens L. Waste ground, infrequent, generally near the coast. 
Reported from Gloucester, West Gloucester, Andover, Malden, 
Revere, Boston, Sherborn. 
SANTALACEAE. 
COMANDRA. 
C. umbellata (L.) Nutt. Dry woods and open ground, very 
common throughout. 
LORANTHACEAE. 
ARCEUTHOBIUM. 
A. pusillum Peck. Parasitic on Picea mariana; at a pond near 
Skug River, Andover (A. S. Pease, Oct. 25, 1902); Wilmington 
CA. S. Pease, Oct. 18, 1902); Acton (J. G. Jack, May 10, 1898). 
ARISTOLOCHIACEAE. 
ASARUM. < 
A. canadense L. Rich woods and roadsides, infrequent. Proba- 
bly introduced at most of its stations. ; 
POLYGONACEAE. 
EMEX. 
E. spinosa Campd. Charlestown (C. E. Perkins, 1882, specimen 
in herb. N. E. Botanical Club). Native of Mediterranean region, 
Cape of Good Hope and the Antilles. 
