Publication: J. Bot. Res. Inst. Texas 12(2): 387 – 444. 2018.
selected vouchers: WTU
Notes: Segregated from Lomatium grayi, which now represents plants south and east of Washington. Most plants previously named L. grayi are now treated as L. papilioniferum, except for some populations in Klickitat County that are now treated as L. klickitatense.