Aconogonon

Handb. Nat. Pfl.-Syst., 236. 1837.

Etymology: Greek acon, whetstone, and gone, seed, perhaps alluding to rough seeds
Basionym: Polygonum sect. Aconogonon Meisner Monogr. Polyg., 55. 1826
Treatment appears in FNA Volume 5. Treatment on page 597. Mentioned on page 479, 481, 574, 581, 600.

Herbs, perennial; roots woody. Stems ascending to erect, glabrous or pubescent to pilose or tomentose. Leaves deciduous, mostly cauline, alternate, petiolate or sessile; ocrea persistent or deciduous, chartaceous; blade narrowly lanceolate to ovate, margins entire, sometimes irregularly undulate. Inflorescences terminal, subterminal, or axillary, racemelike or paniclelike; peduncle present or essentially absent. Pedicels present. 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. Achenes includedor exserted, yellowish or dark-brown, unwinged, 3-gonous, glabrous. Seeds: embryo usually curved. x = 8, 10, 11.

Distribution

w North America, Europe, Asia

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.

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 Aconogonon 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 Aconogonon 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 Aconogonon phytolaccifolium

"/2" is not declared as a valid unit of measurement for this property.

... more about "Aconogonon"
dark-brown;yellowish +
3-gonous +
yellow +  and pink or reddish purple +
ovate +  and elliptic +
Harold R. Hinds† +  and Craig C. Freeman +
not +  and stipelike +
Polygonum sect. Aconogonon +
narrowly lanceolate;ovate +
foliaceous +  and perfoliate +
scale-like +
just below the soil surface or and above the soil surface +  and spreading +
w North America +, Europe +  and Asia +
Greek acon, whetstone, and gone, seed, perhaps alluding to rough seeds +
adnate +, free +  and distinct +
disarticulating +  and solid +
decumbent to erect +  and prostrate +
unwinged +  and winged +
black +, red +, brown +  and yellowish +
exserted +  and included +
pubescent +  and glabrous +
spheroidal +, 4-gonous +, lenticular +, biconvex +, discoid +, 3-gonous +  and 2-gonous +
compound +, branched +  and simple +
axillary +, subterminal +  and terminal +
paniclelike +  and racemelike +
nonmembranous +
sessile +  and petiolate +
deciduous +
pubescent +  and glabrous +
undulate +
swollen +
partly +  and foliaceous +
deciduous +  and persistent +
cylindric +
coriaceous +  and membranous +
anatropous +, , +  and orthotropous +
accrescent +
nonaccrescent +
fleshy +, indurate +  and membranous +
(2-)3(-4)-carpellate +
Handb. Nat. Pfl.-Syst., +
hinds1995a +  and hong1991a +
slender;stout +
not scapose +
ascending +  and erect +
penicillate +, fimbriate +  and capitate +
deciduous +  and persistent +
? (?) +  and ? (?) +
coriaceous +  and membranous +
connate +  and distinct +
spreading;erect +
Aconogonon +
Polygonaceae subfam. Polygonoideae +
lobed +  and laciniate +
coriaceous +
persistent +
membranous +
pubescent +  and glabrous +
11 +, 10 +  and 8 +