Publication: Hist. Pl. Dauphiné 1: 272. 1786.
Origin: Introduced from Europe
Herbarium search: CPNWH
Notes: Several collections from Klickitat County (1911, 1962, 1992), and recently (2018) from King County. Easily confused with G. robertianum, so possibly more widespread than the collecting record indicates.
Last updated 5/16/2020 by David Giblin.