Publication: Trans. Amer. Philos. Soc., n. s. 7: 341. 1840.
selected vouchers: WTU
Notes: FNA19: "Psilocarphus oregonus occurs from west-central California through most of Oregon to southeastern Washington, western Idaho, and northern Nevada. Relatively narrow-leaved, montane forms of P. tenellus account for reports of P. oregonus from the southern Sierra Nevada to Baja California; further study may show these to be intermediates between the two taxa."