A first report of Xeranthemum annuum (Asteraceae: Cardueae) in Montana and North America (U.S.A.)

We report the first North American naturalized occurrence of the genus Xeranthemum L., represented by the occurrence of X. annuum L. on an airstrip in Troy, Montana. We discuss the locality in detail, the number of plants found, include commonly accepted synonyms, and discuss the species’ use in the dried floral industry. An atypical character of the species is the relatively elongated inner phyllary bracts, which are suggestive of ray flowers. Scans of digitized herbarium specimens, including one from the University of Moscow, and one from our novel North American occurrence, are included to show variation in phyllary color.