Eriogonum thymoides |
Eriogonum parvifolium |
|
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thyme buckwheat, thyme wild buckwheat, thyme-leaf buckwheat, thyme-leaf wild buckwheat |
dune wild buckwheat, sea cliff buckwheat, seacliff wild buckwheat |
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Habit | Subshrubs, spreading, polygamodioecious, 0.5–2(–3) × 1–3(–4) dm, tomentose to sericeous. | Shrubs, matted to spreading or rounded, 3–10 × 5–20(–25) dm, thinly tomentose or glabrous, greenish. |
Stems | caudex spreading; aerial flowering stems erect, slender, solid, not fistulose, arising at nodes of caudex branches and at distal nodes of short, nonflowering aerial branches, (0.1–)0.3–0.8(–1.2) dm, tomentose to sericeous, with a whorl of 6–10(–12), leaflike bracts ca. midlength, these similar to leaf blades, 0.3–0.8(–1) × 0.1–0.2 cm. |
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. |
Leaves | in compact basal rosettes, fasciculate, and sheathing up stems; petiole 0.05–0.2 cm; blade linear to narrowly spatulate, (0.2–)0.3–1(–1.5) × 0.1–0.2(–0.3) cm, densely white-tomentose abaxially, silky-villous or sericeous adaxially, margins entire, inrolled to tightly revolute. |
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. |
Inflorescences | capitate, 0.8–2 cm wide; branches absent; bracts absent immediately below involucre. |
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. |
Peduncles | absent. |
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Involucres | 1 per node, turbinate, 3–5 × 2.5–4 mm, villous to sericeous; teeth 6–8, erect, 0.5–1 mm. |
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. |
Flowers | 4–10 mm, including 0.5–1 mm stipelike base; perianth white to pale yellow or yellow, becoming pink to rose, villous abaxially; tepals monomorphic, obovate; stamens included to slightly exserted, 2–4 mm; filaments pilose proximally. |
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. |
Achenes | light brown, 2–2.5 mm, glabrous except for densely pubescent beak. |
brown, 2.5–3 mm, glabrous. |
2n | = 40. |
|
Eriogonum thymoides |
Eriogonum parvifolium |
|
Phenology | Flowering Apr–Jul. | Flowering year-round. |
Habitat | Sandy to gravelly, often volcanic flats, slopes, and outcrops, mixed grassland and sagebrush communities, montane conifer woodlands | Sandy beaches, dunes, and bluffs or sandy to gravelly inland slopes and flats, coastal grassland and chaparral communities, oak and pine woodlands |
Elevation | (200-)600-1700 m ((700-)2000-5600 ft) | 0-300 m (0-1000 ft) |
Distribution |
ID; OR; WA
|
CA
|
Discussion | Eriogonum thymoides is an exquisite species concentrated in three regions of the Pacific Northwest. The first is along the eastern edge of the Cascade Range from near Wenatchee, Washington (Adams, Benton, Chelan, Douglas, Franklin, Grant, Kittitas, Klickitat, Lincoln, and Yakima counties), to near the Dalles in extreme north-central Oregon (Union County). The second is from Baker and northern Malheur counties, Oregon, to Adams, Canyon, and Washington counties, Idaho. A third series of populations is in the Mount Bennett Hills area of Gooding County, Idaho, and just over the borders in Blaine, Camas, Elmore, and Lincoln counties. Staminate plants tend to have yellow flowers that quickly fade after pollen release. Pistillate plants tend to have white to pale yellow flowers that persist and greatly elongate as the achene matures. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 5, p. 360. | FNA vol. 5, p. 300. |
Parent taxa | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oligogonum | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla |
Sibling taxa | ||
Synonyms | E. sphaerocephalum subsp. minimum, E. thymoides subsp. congestum | E. parvifolium var. crassifolium, E. parvifolium subsp. lucidum, E. parvifolium var. lucidum, E. parvifolium subsp. paynei, E. parvifolium var. paynei |
Name authority | Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 9. (1856) | Smith: in A. Rees, Cycl. 13(2): Eriogonum no. 2. (1809) |
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