Eriogonum davidsonii |
Eriogonum racemosum |
|
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Davidson buckwheat, Davidson's buckwheat, Davidson's wild buckwheat |
red-root wild buckwheat, redroot buckwheat |
|
Habit | Herbs, erect, 1–5 dm, glabrous, greenish to grayish. | Herbs, erect to slightly spreading, 3–8(–10) × 0.5–1.5 dm, tomen-tose to floccose or rarely glabrous, grayish. |
Stems | aerial flowering stems erect, 0.5–1.5(–2) dm, glabrous. |
spreading to erect, without persistent leaf bases, up to 1/6 height of plant; caudex stems absent; aerial flowering stems erect to slightly spreading, slender to stout, solid, not fistulose, (1–)1.5–2.5(–3) dm, tomentose to floccose, rarely glabrous. |
Leaves | basal; petiole 1–5 cm, floccose; blade round to reniform, (0.3–)1–2(–4) × (0.3–)1–2(–4) cm, densely white-tomentose abaxially, floccose to glabrate and mostly greenish adaxially. |
basal, 1 per node; petiole (2–)3–10(–15) cm, tomentose to floccose; blade elliptic to ovate or oval to nearly rotund, (1.5–)2–6(–10) × 1–4(–5) cm, lanate to thinly tomentose abaxially, floccose or glabrous and green adaxially, margins plane. |
Inflorescences | cymose, occasionally distally uniparous due to suppression of secondary branches, open, 5–40 × 5–35 cm; branches straight or nearly so, infrequently inwardly curved distally, glabrous; bracts 1–3 × 1–2 mm. |
virgate or racemose with involucres racemosely disposed throughout or at tips, 15–50 × 05–20 cm, tomentose, rarely glabrous; branches dichotomous, upper secondaries suppressed and bearing 5–20(–30) racemosely arranged involucres; bracts 3, scalelike, triangular, and (1–)2.5–7 mm, or leaflike, linear-oblanceolate or oblanceolate to elliptic, and 10–40 × 5–20(–25) mm. |
Peduncles | absent. |
absent or erect, stout, 0.3–4 cm, tomentose to floccose. |
Involucres | appressed to branches, cylindric-turbinate, 3–4 × 2–2.5 mm, glabrous; teeth 5, erect, 0.2–0.3 mm. |
1 per node, turbinate to turbinate-campanulate, (2–)3–5 × (2–)2.5–4 mm, tomentose to floccose; teeth 5, erect, (0.1–)0.2–0.5 mm. |
Flowers | 1.5–2 mm; perianth white to pink or red, rarely yellow, glabrous; tepals monomorphic, oblong-obovate; stamens included, 1–1.5 mm; filaments pilose proximally. |
(2–)2.5–5 mm; perianth white to pinkish, glabrous; tepals connate proximal 1/4, monomorphic, oblong; stamens exserted, 2–5 mm; filaments pilose proximally. |
Achenes | brown, 3-gonous, 2 mm. |
light brown, 3–4 mm, glabrous. |
2n | = 40. |
= 36. |
Eriogonum davidsonii |
Eriogonum racemosum |
|
Phenology | Flowering May–Sep. | Flowering Jun–Oct. |
Habitat | Sandy to gravelly flats and slopes, mixed grassland, saltbush, chaparral, and sagebrush communities, oak and montane conifer woodlands | Sandy to gravelly flats and slopes, mixed grass, sagebrush, and mountain mahogany communities, scrub oak, pinyon, juniper, and conifer woodlands |
Elevation | (400-)900-2600 m ((1300-)3000-8500 ft) | 1400-2900(-3500) m (4600-9500(-11500) ft) |
Distribution |
AZ; CA; NV; UT; Mexico (Baja California)
|
AZ; CO; NM; NV; UT
|
Discussion | 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 racemosum is highly variable in stature, the presence of leaflike bracts in the inflorescences, the size and shape of the leaves, and the length of the mature flowers. None of these features is geographically correlated and thus no taxonomic distinctions are attempted. The species is occasionally cultivated. The tomentose, nonfistulose flowering stems easily distinguish it from Eriogonum zionis. Individuals of E. racemosum with glabrous flowering stems are known (Reveal & Holmgren 1893, BRY, US, UTC; Goodrich 17355, BRY; Neese & White 9237, BRY), but are rare and clearly aberrant expressions. The Navajo or Diné people use the roots of Eriogonum racemosum as a “life medicine,” primarily in the treatment of internal problems, notably poisoning and diarrhea (C. Arnold, pers. comm.; P. A. Vestal 1952). They also use it as an analgesic and orthopedic aid (D. E. Moerman 1986; L. C. Wyman and S. K. Harris 1951); there are reports of its use for venereal disease. Leaves and stems were eaten raw by the Ramah Navajo in northwestern New Mexico (Wyman and Harris). Eriogonum racemosum is the food plant for the Spalding dotted-blue butterfly (Euphilotes spaldingi) and is occasionally visited by the desert green or Comstock’s hairstreak (Callophrys comstocki). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 422. | FNA vol. 5, p. 295. |
Parent taxa | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oregonium | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla |
Sibling taxa | ||
Synonyms | E. molestum var. davidsonii, E. vimineum var. davidsonii, E. vimineum var. glabrum, E. vimineum subsp. juncinellum | E. racemosum var. obtusum, E. racemosum var. orthocladon |
Name authority | Greene: Pittonia 2: 295. (1892) | Nuttall: Proc. Acad. Nat. Sci. Philadelphia 4: 14. (1848) |
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