Arctium tomentosum
 
Cotton Burdock

Mature Flower Head Top

Regina
21-July-2017

Note the involucre is densely arachnoid-tomentose and the bracts are hooked-spiny tipped.

bullet

Tomentosum: Answers to key questions in Budd's Flora and Flora of Alberta leading to this species. 
bullet

involucre densely arachnoid-tomentose; NOT [involucre glabrous, sometimes slightly woolly]

bullet

corolla glandular