Directory       News       Site Map       Home
         
    Jepson eFlora
Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

POLYGONACEAE BUCKWHEAT FAMILY

Mihai Costea & James L. Reveal, family description, key to genera; treatment of genera revised in consultation with James L. Reveal, except as noted


Annual to shrub [tree]. Stem: nodes swollen or not. Leaf: simple, basal or cauline, generally alternate; ocreae present or 0, generally scarious, persistent or not. Inflorescence: flower clusters in axillary to terminal cyme-, panicle-, raceme-, spike-, umbel- or head-like arrangements, entire inflorescence or main inflorescence branches generally subtended by bracts ("inflorescence bracts"); peduncles present or 0; flower clusters in Eriogoneae-Eriogonoideae subtended by involucre of >= 1 free or ± fused, sometimes awn-tipped bracts ("involucre bracts") or, in Polygonoideae and rarely in Eriogonoideae, not (if bracts completely fused, involucre "tubular"); pedicels in Eriogoneae each often subtended by 2 free, transparent, linear bractlets or in Polygonoideae all subtended by 2+ fused, membranous, wide bractlets. Flower: generally bisexual, small, 1–200 per node; perianth parts 2–6, generally in 2 whorls, free or basally fused, generally petal-like, often ± concave adaxially, often darker at midvein, often turning ± red or ± brown in age; stamens [1]3 or 6–9 in 2 whorls; ovary superior, 1-chambered, ovule 1, styles 1–3. Fruit: achenes, included in or exserted from perianth, generally 3-angled, ovoid or elliptic, generally glabrous.
48 genera, ± 1200 species: worldwide, especially northern temperate; some cultivated for food (Coccoloba, sea-grape; Fagopyrum, Rheum, Rumex) or ornamental (Antigonon, lovechain; Coccoloba; Muehlenbeckia; Persicaria; Polygonum), a few timbered (Coccoloba; Triplaris). Several (Emex; Fallopia; Persicaria; Polygonum; Rumex) are weeds. [Freeman & Reveal 2005 FNANM 5:216–601] Treatment of genera in Eriogonoideae based on monographic work of James L. Reveal. Involucre number throughout is number (1–many) per ultimate grouping, at tips of ultimate branches; flower number is per flower cluster or involucre, unless otherwise stated. Fagopyrum esculentum Moench not naturalized, considered an historical waif (or garden weed ± presently), therefore not treated. —Scientific Editor: Thomas J. Rosatti.

Key to Polygonaceae

1. Ocreae present, persistent or not; nodes generally swollen; flower cluster not subtended by involucre; pedicels all subtended by 2+ fused, membranous, wide bractlets (Polygonoideae)

2. Perianth parts (5)6 (Rumiceae)

3. Flowers unisexual, outer perianth parts of pistillate flower spine-tipped in fruit ..... EMEX

3' Flowers generally bisexual, outer perianth parts not spine-tipped in fruit ..... RUMEX

2' Perianth parts 4–5

4. Perianth parts 4; fruit elliptic, 2-winged; leaves ± basal ..... OXYRIA

4' Perianth parts 4–5; fruit generally ovoid; leaves generally cauline

5. Vine-like shrub; perianth in fruit fleshy (Coccolobeae) ..... MUEHLENBECKIA

5' Herb, or if shrub then not vine-like; perianth in fruit generally not fleshy (Polygoneae)

6. Outer perianth parts winged or keeled, or ± so

7. Flower base stalk-like; outer perianth parts winged (keeled in Fallopia convolvulus); leaf blade sagittate or cordate; ocrea papery, not 2-lobed distally ..... FALLOPIA

7' Flower base not stalk-like; outer perianth parts keeled; leaf blade not sagittate or cordate; ocrea generally translucent, 2-lobed distally ..... POLYGONUM (2)

6' Outer perianth parts not winged or keeled

8. Leaves generally basal; inflorescence terminal, spike-like; stems not branched ..... BISTORTA

8' Leaves cauline; inflorescence terminal, axillary, spike-like or not; stems generally branched

9. Ocreae generally translucent, glabrous, 2-lobed, fibrous in age ..... POLYGONUM (2)

9' Ocreae opaque, glabrous to scabrous, not 2-lobed

10. Inflorescence raceme- or panicle-like; perianth parts fused ± 1/4; stamens 8 ..... ACONOGONON

10' Inflorescence ± head-, spike-, or panicle-like; perianth parts fused 1/4–2/3; stamens 5–8 ..... PERSICARIA

1' Ocreae 0; nodes not swollen; flower clusters subtended by involucre of 1+ free or fused bracts (or not, in Gilmania); pedicels each often subtended by 2 free, transparent, linear bractlets (Eriogoneae-Eriogonoideae)

11. Involucre bract 1, inflated, awns 0; leaves generally lobed; stamens 6 (Pterostegiinae) ..... PTEROSTEGIA

11' Involucre 0 or tubular or of 2–5 ± free bracts, not inflated, awned or not; leaves entire; stamens 3–9 (Eriogoninae)

12. Annual to shrub, if annual then involucre tubular, awnless

13. Involucres of 2–5 awnless bracts ..... DEDECKERA

13' Involucres tubular ..... ERIOGONUM

12' Annual; involucres tubular and awned or of free or basally fused bracts, awned or not, 0 in Gilmania

14. Leaves basal and cauline, opposite ..... GOODMANIA

14' Leaves basal or if cauline then alternate or whorled

15. Involucre 0 ..... GILMANIA

15' Involucre present

16. Involucres of free or basally fused bracts

17. Stamens 3

18. Perianth lobes leathery; involucre bracts 3, awned ..... LASTARRIAEA

18' Perianth lobes petal-like; involucre bracts many, awnless ..... NEMACAULIS

17' Stamens 6 or 9

19. Involucre bracts 3(4), awned; plant tomentose ..... HOLLISTERIA

19' Involucre bracts 4–7, awnless; plant silky-puberulent ..... JOHANNESHOWELLIA

16' Involucres tubular

20. Involucre funnel- to bell-shaped, not angled, not ridged

21. Involucre awns 5(6); perianth lobes 3-lobed to fringed ..... SIDOTHECA

21' Involucre awns (3)4(5) or 7–36; perianth lobes generally entire

22. Involucre awns 4(5) or generally 7–30(36) ..... ACANTHOSCYPHUS

22' Involucre awns (3)4 ..... OXYTHECA

20' Involucre generally ± cylindric, angled or not, ridged or not

23. Bracts generally 2, opposite, or many, whorled; flowers 1(2) ..... CHORIZANTHE

23' Bracts 3, alternate, on 1 side of branch or not; flowers (1)2–6

24. Involucre teeth 5, awns at tips; flowers 4(6) ..... ARISTOCAPSA

24' Involucre teeth 2–4 or 6, if 5 then awns both at base of involucre and at tips of teeth; flowers (1)2–3

25. Involucre not awned basally

26. Flower hairy; bracts below involucre obvious; involucre teeth unequal ..... MUCRONEA

26' Flower glabrous, bumpy; bracts below involucre obscure; involucre teeth equal ..... SYSTENOTHECA

25' Involucre awned basally

27. Involucre 3-angled, basal awns 3, terminal (on teeth) 5; flowers 2 ..... CENTROSTEGIA

27' Involucre 6-angled, basal awns 6, terminal (on teeth) 6; flowers 3 ..... DODECAHEMA

Contact/Feedback

Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
We encourage links to these pages, but the content may not be downloaded for reposting, repackaging, redistributing, or sale in any form, without written permission from The Jepson Herbarium.