Flora of North America species comparison

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Aconogonon

Aconogonon davisiae

fleeceflower

Davis' knotweed, Newberry's fleeceflower, Newberry's knotweed
Habit Herbs, perennial; roots woody. Plants 12–42(–50) cm.
Stems

ascending to erect, glabrous or pubescent to pilose or tomentose.

ascending to erect, glabrous or pubescent.
Leaves

deciduous, mostly cauline, alternate, petiolate or sessile;

ocrea persistent or deciduous, chartaceous;

blade narrowly lanceolate to ovate, margins entire, sometimes irregularly undulate.

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.
Inflorescences

terminal, subterminal, or axillary, racemelike or paniclelike;

peduncle present or essentially absent.

axillary, racemelike;

peduncle essentially absent.
Pedicels

present.

0.5–1.9(–2.4) mm.
Flowers

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.

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.
Achenes

includedor exserted, yellowish or dark brown, unwinged, 3-gonous, glabrous.

exserted, yellowish brown, not beaked distally, 3.2–6(–8.3) × 2.1–5 mm, shiny, faces not concave.
Seeds

embryo usually curved.

x

= 8, 10, 11.

2n

= 20.

Aconogonon

Aconogonon davisiae
Distribution
w North America; Europe; Asia
[BONAP county map]
from FNA
CA; ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

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.)
Key
1. Inflorescences axillary, racemelike; plants 12-42(-50) cm; leaf blades oblong-ovate to ovate, rarely broadly lanceolate, 2.1-7.5(-9.7) × 1.1-5 cm, often glaucous
A. davisiae
1. Inflorescences usually terminal or subterminal, sometimes also axillary, paniclelike; plants (30-)50-150(-200) cm; leaf blades narrowly lanceolate to ovate, 5-20 × 1.4-8 cm, not glaucous
→ 2
2. Achenes 2.6-3.8 mm, included or exserted, tan to grayish, faces usually not concave; inflorescences terminal, sometimes also axillary; Alaska, n Yukon, nw Northwest Territories
A. alaskanum
2. Achenes (3-)3.8-7 mm, usually exserted, yellowish brown, faces concave; inflorescences usually terminal, subterminal, and axillary; n California, Oregon, Washington, Idaho, w Montana, n Nevada
A. phytolaccifolium
1. Faces of leaf blades pubescent, rarely glabrescent
var. davisiae
1. Faces of leaf blades glabrous
var. glabrum
Source FNA vol. 5, p. 597. Authors: Harold R. Hinds†, Craig C. Freeman. FNA vol. 5, p. 599.
Parent taxa Polygonaceae > subfam. Polygonoideae Polygonaceae > subfam. Polygonoideae > Aconogonon
Sibling taxa
A. alaskanum, A. phytolaccifolium
Subordinate taxa
A. alaskanum, A. davisiae, A. phytolaccifolium
A. davisiae var. davisiae, A. davisiae var. glabrum
Synonyms Polygonum section A. Polygonum davisiae, A. newberryi, Polygonum newberryi
Name authority unknown: Handb. Nat. Pfl.-Syst., 236. (1837) (W. H. Brewer ex A. Gray) Soják: Preslia 46: 151. (1974)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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