Aconogonon davisiae |
Aconogonon |
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Davis' knotweed, Newberry's fleeceflower, Newberry's knotweed |
fleeceflower |
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Habit | Plants 12–42(–50) cm. | Herbs, perennial; roots woody. | ||||||||||||
Stems | ascending to erect, glabrous or pubescent. |
ascending to erect, glabrous or pubescent to pilose or tomentose. |
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Leaves | ocrea reddish brown, funnelform, 0.3–3 cm, margins oblique, glabrous or finely pubescent to pilose; petiole 0.3–10(–15) mm; blade oblong-ovate to ovate, rarely broadly lanceolate, 2.1–7.5(–9.5) × 1.1–5 cm, subcoriaceous, base truncate or, rarely, cordate, margins entire, glabrous or ciliate, apex obtuse to acute, faces often glaucous, glabrous or pubescent. |
deciduous, mostly cauline, alternate, petiolate or sessile; ocrea persistent or deciduous, chartaceous; blade narrowly lanceolate to ovate, margins entire, sometimes irregularly undulate. |
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Inflorescences | axillary, racemelike; peduncle essentially absent. |
terminal, subterminal, or axillary, racemelike or paniclelike; peduncle present or essentially absent. |
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Pedicels | 0.5–1.9(–2.4) mm. |
present. |
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Flowers | 1–4 per ocreate fascicle, rarely some flowers with stamens poorly developed; perianth greenish to pinkish white, 2–4.5 mm; tepals slightly dimorphic or, rarely, distinctly so, oblong-ovate to obovate, apex obtuse; anthers yellow or pink. |
bisexual, 1–5 per ocreate fascicle, base stipelike or not; perianth nonaccrescent, creamy or greenish to yellowish white or pink, rotate, glabrous; tepals 5, connate ca. 1/4 their length, petaloid, slightly to distinctly dimorphic, outer 2 smaller than inner 3; stamens 8; filaments distinct, free or adnate to perianth tube, glabrous; anthers yellow to pink or reddish purple, ovate to elliptic; styles 3, erect or spreading, distinct or connate proximally; stigmas capitate. |
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Achenes | exserted, yellowish brown, not beaked distally, 3.2–6(–8.3) × 2.1–5 mm, shiny, faces not concave. |
includedor exserted, yellowish or dark brown, unwinged, 3-gonous, glabrous. |
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Seeds | embryo usually curved. |
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x | = 8, 10, 11. |
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2n | = 20. |
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Aconogonon davisiae |
Aconogonon |
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Distribution |
CA; ID; OR; WA
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w North America; Europe; Asia |
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Discussion | Varieties 2 (2 in the flora). The varieties are largely sympatric and often intergrade. The treatment here follows Hong S. P. (1991). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species ca. 25 (3 in the flora). The orthography of and author citation for the genus name have been matters of confusion. Meisner published the taxon as Polygonum sect. Aconogonon. Reichenbach elevated it to generic rank and changed the orthography, apparently deliberately, to Aconogonum. Debate centers on whether Reichenbach’s name is new (Aconogonum Reichenbach) or should be treated as Meisner’s section name elevated to generic rank [Aconogonon (Meisner) Reichenbach]. Following established custom, we here use Aconogonon. Aconogonon often is treated as a section of Persicaria (L.-P. Ronse Decraene and J. R. Akeroyd 1988); pollen morphology, inflorescence type, and seed and stem anatomy have been used by some taxonomists for segregation at the generic level (K. Haraldson 1978; Hong S. P. 1991). Aconogonon campanulatum (Hooker f.) H. Hara is planted as an ornamental. C. L. Hitchcock and A. Cronquist (1973) reported it as escaping and probably established west of the Cascade Mountains, especially in Seattle, Washington. P. Zika (pers. comm.) searched numerous herbaria in the Pacific Northwest. He found no voucher indicating that A. campanulatum has escaped there, although it is cultivated occasionally in the Seattle area; it therefore is excluded here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 5, p. 599. | FNA vol. 5, p. 597. | ||||||||||||
Parent taxa | Polygonaceae > subfam. Polygonoideae > Aconogonon | Polygonaceae > subfam. Polygonoideae | ||||||||||||
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Subordinate taxa | ||||||||||||||
Synonyms | Polygonum davisiae, A. newberryi, Polygonum newberryi | Polygonum section A. | ||||||||||||
Name authority | (W. H. Brewer ex A. Gray) Soják: Preslia 46: 151. (1974) | unknown: Handb. Nat. Pfl.-Syst., 236. (1837) | ||||||||||||
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