Publication: Syn. Fl. N. Amer. 1(1,1): 144. 1895.
selected vouchers: WTU
Notes: FNA7: "rysimum occidentale is restricted to sand deposits along or near the Columbia River and its tributaries. It is distributed in Gilliam, Hood River, Morrow, Sherman, and Umatilla counties in Oregon, and in Franklin, Grant, Kittitas, Klickitat, Lincoln, Walla Walla, and Yakima counties in Washington."