LIST OF HIGHER SEED-PRODUCING PLANTS. 535 
Ambrosia trifida Linn. Spec. 987.(1758). 
Wats. and Coult., Gray’s Man. 6 ed. 273; Britt., Fl. N. J. 148; Webb., 
Fl. Neb. 147, Mac., Fl. Can. I, 240; Chap., Fl. S. St. 223; Coult., Fl. Colo. 
180; Upham, Fl. Minn. 79; Mac., Fl.Can. I, 549; Roth., Wheel. Exp. 158; 
Cov., Fl. Ark. 194; Gray, Syn. FI. I, 2, 249; Coult., Fl. Tex. 209. 
North America: Q., Ont. to Man. and Colo.; 8. to Mo., 
Tex., Ark. and Fla. 
Minn. valley: Throughout; gullies, ravines and thick- 
ets or along roads. 
Hers.: Ballard 845, Page lake, Carver Co.; Taylor 
1029, Glenwood; Sandberg 314, Goodhue Co.; Herb. Moyer 133, 
Montevideo. 
Ambrosia trifida Linn. var. integrifolia (MUHL.) T. and G 
Fi. II, 354 (1841). 
A, integrifolia MuHL. Willd. Spec. 1V, 375 (1805). 
Wats. and Coult., Gray’s Man. 6 ed. 273; Britt., Fl. N. J. 143; Upham, 
Fl. Minn. 79; Mac., Fl. Can. I, 240; Chap., Fl. S. St. 223; Gray, Syn. Fl. 
I, 2, 249. 
North America: With species; westward; Ills. to N. 
Y. and Va. 
Minn. valley: Throughout at higher levels; local or 
infrequent; habitat with the species. 
HERB.: Sheldon 1382, Lake Benton. 
XANTHIUM Linn. Gen. 717 (1737). 
; Baillon, Hist. Pl. VIII, 287; Benth. and Hook., Gen. Pl. II, 355; Eng- 
ler and’Prantl, Nat. Pflanz. IV, 5, 222; Durand, Ind. Gen. Phan. 207. 
Living species: 3-4; temperate and warmer regions, 
around the world. Russia. 3; Europe, 3; Russian Europe, 2; 
N. America, 3-4; Canada, 1-2; California, 1; Rocky mts., 1; 
E. Sts., 1-2; W. Tex., 2-3. 
Xanthium canadense MILL. Dict. ed. 8 (1768). 
X, orientale LINN. Spec. (1753) in part. 
X. carolinense DILL. Elth. II, 432 (1774). 
X. americanum Wat. FI. Car. 231 (1788). 
X. macrocarpum var. glabratum DC. Prodr. V, 523 (1836). 
X. strumarium var. canadense T. and G. FI. II, 294 (1841). 
X. strumarium AuUCT. AMER. 
Wats. and Coult., Gray’s Man. 6 ed. 274; Coult., Fl. Colo., 182; Webb., 
Fl. Neb. 147; Mac., Fl. Can. I, 241; Upham, Fl. Minn. 79; Chap., Fl. 8. 
St. 224; Roth., Wheel. Exp. 159; Wats,, King Exp. 166; Eng]. Hoffmann, 
Nat. Pflanz. IV, 5, 223; Gray, Syn. Fl. I, 2, 252; Coult Fl. Tex. 211. 
North America: N. W. T. to Tex.; W. to Calif. and 
Nev.; E. to Saskatchewan, Minn., Neb., Ark.? Ga. 
Minn. valley: Throughout, especially N. E.; sterile 
places, banks and fields. 
