Flora of North America species comparison

Eriogonum davidsonii is widespread and mostly common to occasionally abundant or weedy in Arizona, California, southern Nevada, and southern Utah. It is exceedingly variable. In the northern part of California, its range approaches that of E. luteolum var. luteolum, and the two can be difficult to differentiate. To the south, in Tulare County, the distinction between E. davidsonii and E. luteolum var. pedunculatum also is difficult. Specimens of Eriogonum davidsonii with curved inflorescence branches resemble E. cithariforme in the mountains of southern California, and care must be taken to separate E. davidsonii from its more robust relative, E. molestum in the San Jacinto Mountains of Riverside County. The disjunct populations in Utah and Arizona are somewhat different in appearance but presently do not seem worthy of taxonomic separation. The epithet juncinellum is available should recognition be desired.

Seeds of Davidson’s wild buckwheat were pounded into a meal and eaten dry by the Kawaiisu people of southern California (M. L. Zigmond 1981).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Eriogonum leptophyllum is found mainly on southern Colorado Plateau in San Juan County, Utah, and adjacent Montezuma County, Colorado, southward into Apache County, Arizona, and in northwestern New Mexico (Bernalillo, Cibola, McKinley, Rio Arriba, Sandoval, San Juan, Santa Fe, and Taos counties). The species is found rarely in eastern Coconino and Navajo counties, Arizona, in the north, and in northern Gila County, Arizona, to the south. It is disjunct to the Bitter Spring Creek area of Capitol Reef National Park in Garfield County, Utah (R. Fleming 199, SJNM). The species, when dwarfed as it sometimes is on wind-swept ridges, resembles E. microthecum var. simpsonii, and has a form and aspect much more typical of that species than of the large, mature plants of E. leptophyllum. Mature plants on the southern edge of the range (as in McKinley County) tend to be grayish rather than the more common yellowish green seen elsewhere.

This species is considered a “life medicine” by the Navajo (Diné) people (C. Arnold, pers. comm.), being used in a variety of ways, including as an analgesic, a gynecological aid, a snake-bite remedy (D. E. Moerman 1986), and in casting spells (Arnold Clifford, pers. comm.). P. A. Vestal (1952) listed similar uses of this species by the Ramah Navajo of northwestern New Mexico, including an infusion of roots for stomach trouble, a decoction of the whole plant for snake bite, and for postpartum pain. The species is cultivated occasionally as a horticultural novelty.

There are two anomalous populations of particular interest. These occurred in the Broomfield area of San Juan County, New Mexico. The specimens are of low, spreading herbs to 0.8 dm with linear-oblong leaf blades 1–2 cm long but only 1–2 mm wide. The inflorescences are cymose but typically with one branch suppressed. A peduncle is present in some, this being up to 3.5 mm and erect; it is always at the basal node of the inflorescence. The involucres are turbinate and long (4–6 mm). A mature achene has not been observed. The plants flowered in late May and early June. Efforts to find such plants again have been unsuccessful. Searches in the late summer and early fall, when they ought to be in fruit, have found only plants that clearly can be assigned to Eriogonum leptophyllum. Generally, the two anomalous collections, both made by J. Mark Porter in the 1980s, resemble that species. Until such odd plants can be found again, and studied in detail, the significance of those populations cannot be ascertained.

(Discussion copyrighted by Flora of North America; reprinted with permission.)