University of California Publications in Botany 34:80. 1962. Brittonia 16(3):281. 1964.

In cinder soil on east side, base of Vulcan's Throne, Toroweap Valley, at 4,200 feet elevation, Grand Canyon National Monument, Mohave County, Arizona, April 30, 1952 E. McClintock 52-0294 (holotype : CAS 373481; isotypes: ARIZ, NY, WS).

Dr. Elizabeth McClintock made the original collection of Camissonia confertiflora on the east base of Vulcan's Throne on the southern end of Toroweap or Tuweep Valley on April 30, 1952. She and Dr. Walter Cottam (who also made a collection of the new species) were botanically exploring a remote area of Grand Canyon National Monument (McClintock 1952, Cottam 1956).

In 1962, Dr. Peter Raven described the species, naming it Oenothera confertiflora. In 1964, Raven revised the concept of the genera of the Onagraceae, tribe Onagreae, naming the taxon Camissonia confertiflora, within the section Chylismia. Raven used the distinguishing characters of sepals with free caudate tips arising just below the apices, glandular pubescence on the sepals, and stamens differentiated into two sets of different lengths. He separated it from C. brevipes, which has sub-equal or widespread stamens. In 1969, this interpretation was reiterated, along with the statement that no more was known about this species than what was described in 1962 (Raven 1969).

Dr. Arthur M. Cronquist, however, submerged the species into the widespread and variable Camissonia brevipes (A. Gray) Raven (Cronquist et al. 1997). This was based on the fact that, while plants recognized as C. confertiflora had sub-mature fruits circa 5 cm long, scarcely four times as long as the 13 mm long pedicel, they were scarcely distinctive in the context of the general C. brevipes population.

Dr. Warren L. Wagner, slated to write the treatment of the Camissonia for the upcoming Arizona Flora, plans to recognize C. confertiflora. However, he has stated that this means little since the taxon is so rare and is located in an area where not many botanists have prepared floristic treatments. Lehr (1978) and McDougal (1973) do not recognize C. confertiflora as a member of the Arizona flora but do recognize C. brevipes.