Xanthium aridum

Washington: Benton: In Black Canyon, Rattlesnake Hills. Elev. 2400 ft
46.418026° N, 119.79261° W,
Gravel benches. HerbariumSpecimenDuplicate: Xanthium aridum Type. Northw. Sci. 2: 93, 1928. Https://intermountainbiota.org/portal/collections/individual/index.php?occid=30839573. Phenology: fruiting. Type specimen (basionym and designation not recorded).

Harold St. John; C. English 8100, Apr 8, 1927
With G. N. Jones, L. A. Mullen
WS, Catalog: 46774, WS000530

Xanthium aridum St. John

Washington: Benton: In Black Canyon, Rattlesnake Hills. Elev. 2400 ft
46.418026° N, 119.79261° W,
Gravel benches. HerbariumSpecimenDuplicate: Xanthium aridum Type. Northw. Sci. 2: 93, 1928. Now considered a synonym of Xanthium strumarium var. glabratum. Https://intermountainbiota.org/portal/collections/individual/index.php?occid=30839574. Phenology: fruiting. Type specimen (basionym and designation not recorded).

Harold St. John; C. English 8100, Apr 8, 1927
With G. N. Jones, L. A. Mullen
WS, Catalog: 46775, WS000529