Single Record

Species: Oenothera pallida [Oenothera trichocalyx] [Oenothera runcinata] [Oenothera albicaulis var. runcinata] etc.

PhotoRecords: YES Rich Haswell: Rio Grande Co, just south of Del Norte, 14-16 July 2023 (var. trichocalyx); Scott F. Smith, west of Villa Grove, 16 June 2024.

Comments: Two varieties or subspecies of Oenothera pallida have been recorded from the Watershed: var. runcinata from dry or sandy locations in the eastern Upper Basin, and var. trichocalyx from dry slopes of pinyon-juniper habitat on the western side. Two anomalous records need to be confirmed (Terrace Reservoir in Conejos Co and Del Norte Ranger Station in Rio Grande Co). Note that O. pallida has many subspecies or varieties, with much intergrading of features. O. pallida is a Central and Northern Rockies and Great Basin evening-primrose that follows the Rio Grande drainage through New Mexico almost to the Big Bend of Texas. In the Watershed, vouchers have been determined as var. trichocalyx or var. runcinata, but var. pallida may be present in sandy places, just unrecorded . Note that in the Watershed, O. pallida subsp. trichocalyx can be mistaken for O. albicaulis . The surest way to distinguish them is by their capsules (seedpods). That of O. pallida subsp. trichocalyx is covered with long hairs and more or less round in cross section. That of O. albicaulis is much less hairy and four-angled in cross section. Incidentally, the voucher determined as "Oenothera engelmannii" by S. Stecher from near San Luis Lake (1988, Alamosa Co) is probably O. pallida.