Oxytheca dendroidea subsp. dendroidea |
Polygonaceae subfam. eriogonoideae |
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narrow-leaf oxytheca, tall oxytheca, treelike puncture-bract, treeline puncturebract |
wild buckwheat |
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Habit | Plants erect to spreading, 0.4–4 × 0.3–4.5 dm. | Shrubs, subshrubs, or herbs, sometimes nearly arborescent (Eriogonum), perennial, biennial, or annual, homophyllous, polycarpic (rarely monocarpic in Eriogonum); taproot solid or, rarely, chambered (Eriogonum), slender to stout. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | sparsely to densely glandular. |
prostrate or decumbent to spreading or erect, sometimes scapose, rarely absent (Eriogonum), without recurved spines, glabrous or pubescent, sometimes glandular; nodes not swollen; tendrils absent; caudex stems tightly compact to spreading and at or just below the soil surface or spreading to erect and above the soil surface, woody; aerial flowering stems decumbent to spreading or erect, arising at nodes of caudex branches, at distal nodes of aerial branches, or directly from the root, slender to stout and solid or slightly to distinctly fistulose, rarely disarticulating in ringlike segments (Eriogonum). |
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Leaves | blades linear to linear-oblanceolate, 1–4.5 × 0.1–0.7 cm, densely hirsute, sparsely glandular. |
deciduous (persistent in some shrubby and matted Eriogonum species), basal or basal and cauline, rarely only cauline, rosulate, alternate, or infrequently opposite (Goodmania) or in whorls of 3 (Gilmania); stipules absent (possibly vestigial in some perennial species of Chorizanthe); petiole present, sometimes indistinct, not articulate or with extrafloral nectaries; blade simple, rarely lobed (Pterostegia), rarely awn-tipped (Goodmania). |
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Inflorescences | open to diffuse, 0.5–4 dm; bracts (2–)3(–4) at first node, otherwise 2–3 and distinct or basally connate, linear to subulate or triangular, 1–18 × 0.5–4 mm, scalelike or sometimes leaflike, hirsute and glandular; awns 0.2–0.5 mm, often absent at distal nodes. |
terminal or terminal and axillary, cymose and dichotomously or trichotomously branched, or racemose, simple or compound umbellate, or capitate; bracts usually connate proximally, leaflike or scalelike, entire apically, sometimes awn-tipped, glabrous or pubescent. |
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Peduncles | occasionally absent at distal nodes, erect or deflexed, slender, 0.5–1.5 cm. |
absent or erect to deflexed relative to inflorescence branch, sometimes reflexed, straight or curved. |
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Involucres | 1–2 mm, typically glabrous, rarely with few scattered hairs abaxially; teeth (3–)4; awns grayish, 0.5–3 mm. |
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Flowers | 2–6; perianth white to pink, 1–2 mm, glabrous or strigose and sparsely glandular abaxially; tepals dimorphic, margins essentially entire, those of outer whorl elliptic to ovate and pubescent adaxially, those of inner whorl elliptic or oblong to narrowly ovate and glabrous or sometimes strigose adaxially proximally; filaments 0.5–1.5 mm, glabrous; anthers cream to red, oval, 0.2–0.3 mm. |
(1–)2–30(–100) per involucral structure, occasionally with stipelike base distal to articulations (Eriogonum); perianth accrescent in fruit, mostly white to red, yellow, light green, greenish white, maroon, or purple, urceolate to campanulate, occasionally glandular or pustulose abaxially, nearly always minutely glandular along midvein adaxially, glabrous or pubescent; tepals (5–)6, in 2 whorls of 3, connate proximally, typically not forming tube (except Chorizanthe, Lastarriaea, Mucronea, Pterostegia), petaloid or, rarely, coriaceous (Lastarriaea), monomorphic or dimorphic, entire, emarginate, or lobed to laciniate apically, rarely awn-tipped (Lastarriaea) or apiculate (Eriogonum); nectary a disk at base of ovary; stamens 3, 6, or 9 (variously 3–9 in Chorizanthe, Mucronea); staminodes absent; filaments usually distinct, occasionally forming staminal tube (Chorizanthe); pistils 3-carpellate, homostylous; ovary 1-locular; ovule 1, orthotropous, placentation basal; styles 3, distinct; stigmas capitate. |
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Achenes | yellow-brown to maroon, 2–2.5 mm. |
brown to black or maroon, homocarpic, winged or unwinged, 3-gonous, less often lenticular or globose-lenticular to globose. |
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Seeds | embryo straight or curved. |
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Involucral | structures tubular (involucre) or consisting of a series of individual bractlike lobes (involucral bracts) arranged in whorls or spirals, rarely absent (Gilmania), awns present or absent; involucre cylindric, prismatic, turbinate, campanulate, urceolate, or funnelform with 3–8(–36) usually erect teeth or 4–12 spreading to reflexed lobes (teeth and lobes are distal portions of proximally connate involucral bracts); involucral bracts in 1–3 whorls, rarely in spirals (Johanneshowellia), free or connate only at base, linear to oblanceolate or ovate. |
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2n | = 40. |
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Oxytheca dendroidea subsp. dendroidea |
Polygonaceae subfam. eriogonoideae |
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Phenology | Flowering Jun–Oct. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Dry, sandy to rocky flats, washes, and slopes in mixed grassland, saltbush, sagebrush communities, pinyon and/or juniper and montane conifer woodlands | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 300-3000 m (1000-9800 ft) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
CA; ID; NV; OR; WA; WY |
Mainly temperate regions of w North America (Alaska to Mexico); uncommon in South America (Argentina and Chile) and e North America (WVa s to c Fla, e to Mo, Okla, and Tex) |
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Discussion | Subspecies dendroidea is common and widespread in western North America from southeastern Oregon to southwestern Wyoming southward into eastern California (as far south as Inyo County), Nevada (to Nye County), but surprisingly unknown from northern Utah. Populations in Washington and Wyoming are extensions of the Snake River Plains populations found in Idaho. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 20, species ca. 325 (19 genera, 281 species in the flora). Detailed habitat, elevation, and distribution data for the eriogonoid genera are maintained by the author and available on the Web at: “Eriogonoideae (Polygonaceae) of North America north of Mexico” (http://www.life.umd.edu/emeritus/reveal/pbio/eriog/key.html). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 5, p. 435. | FNA vol. 5, p. 218. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Name authority | unknown | Arnott: in M. Napier, Encycl. Brit. ed. 7, 5: 126. (1832) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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