Eriogonum parvifolium |
Eriogonum davidsonii |
|
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dune wild buckwheat, sea cliff buckwheat, seacliff wild buckwheat |
Davidson buckwheat, Davidson's buckwheat, Davidson's wild buckwheat |
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Habit | Shrubs, matted to spreading or rounded, 3–10 × 5–20(–25) dm, thinly tomentose or glabrous, greenish. | Herbs, erect, 1–5 dm, glabrous, greenish to grayish. |
Stems | spreading, sometimes matted, often with persistent leaf bases, up to 1/2 or more height of plant; caudex stems absent or matted; aerial flowering stems prostrate, spreading, or erect, slender, solid, not fistulose, 0.2–1 dm, thinly tomentose or glabrous. |
aerial flowering stems erect, 0.5–1.5(–2) dm, glabrous. |
Leaves | cauline, fasciculate, infrequently 1 per node; petiole 0.1–0.7 cm, floccose; blade lanceolate to round, 0.5–3 × 0.3–0.8(–1.2) cm, lanate to tomentose abaxially, mostly glabrous and olive green to green adaxially. |
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. |
Inflorescences | capitate to cymose, 20–30 × 2–10 cm; branches dichotomous, thinly tomentose or glabrous; bracts 3, scalelike, triangular, and 1–2 mm, or leaflike, usually elliptic, and 5–20 × 2–10 mm. |
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. |
Peduncles | absent. |
absent. |
Involucres | 2–7 per cluster, turbinate-campanulate, (2.5–)3–4 × 2–3.5 mm, floccose to glabrate; teeth 5, erect, 0.5–0.9 mm. |
appressed to branches, cylindric-turbinate, 3–4 × 2–2.5 mm, glabrous; teeth 5, erect, 0.2–0.3 mm. |
Flowers | 2.5–3 mm; perianth white to pinkish or greenish yellow, glabrous; tepals connate proximally, monomorphic, obovate; stamens exserted, 2.5–3.5 mm; filaments pilose proximally. |
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. |
Achenes | brown, 2.5–3 mm, glabrous. |
brown, 3-gonous, 2 mm. |
2n | = 40. |
= 40. |
Eriogonum parvifolium |
Eriogonum davidsonii |
|
Phenology | Flowering year-round. | Flowering May–Sep. |
Habitat | Sandy beaches, dunes, and bluffs or sandy to gravelly inland slopes and flats, coastal grassland and chaparral communities, oak and pine woodlands | Sandy to gravelly flats and slopes, mixed grassland, saltbush, chaparral, and sagebrush communities, oak and montane conifer woodlands |
Elevation | 0-300 m (0-1000 ft) | (400-)900-2600 m ((1300-)3000-8500 ft) |
Distribution |
CA
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AZ; CA; NV; UT; Mexico (Baja California)
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Discussion | The native range of Eriogonum parvifolium is restricted to coastal and near-coastal areas (Los Angeles, Monterey, Orange, San Diego, San Luis Obispo, Santa Barbara, and Ventura counties). The coastal expression (var. parvifolium) has thickened leaf blades (0.5–1.5 × 0.3–0.8 cm) and simple or dichotomous inflorescences of compact clusters of involucres containing white to rose flowers. Highly compact and dense mat-forming plants on rocky bluffs immediately next to the ocean were named var. crassifolium; those with yellow flowers were named var. lucidum. The inland form with thin leaf blades (1.5–3 × 0.3–0.8 cm) and highly-branched, cymose, white-flowered inflorescences is perhaps worthy of continued recognition as var. paynei, although there is no sharp distinction between the extremes. Several expressions of the seacliff wild buckwheat are in cultivation, and unfortunately the California Department of Transportation is using the species in roadside plantings, with the result that it is now established in Santa Clara County. Every effort should be made to halt its introduction beyond its native range. The species is the food plant for two federally endangered butterflies, the El Segundo dotted-blue (Euphilotes battoides allyni), near Los Angeles, and Smith’s dotted-blue (Euphilotes enoptes smithi), near Monterey. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 5, p. 300. | FNA vol. 5, p. 422. |
Parent taxa | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oregonium |
Sibling taxa | ||
Synonyms | E. parvifolium var. crassifolium, E. parvifolium subsp. lucidum, E. parvifolium var. lucidum, E. parvifolium subsp. paynei, E. parvifolium var. paynei | E. molestum var. davidsonii, E. vimineum var. davidsonii, E. vimineum var. glabrum, E. vimineum subsp. juncinellum |
Name authority | Smith: in A. Rees, Cycl. 13(2): Eriogonum no. 2. (1809) | Greene: Pittonia 2: 295. (1892) |
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