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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.



Scott Simono

Annual to perennial herb; glabrous or papillate and hairy; rhizomed, stoloned, or generally from taproot with a short caudex; occasionally dioecious. Stem: prostrate, decumbent, or generally erect to ascending, often ± ridged, red-brown in fruit, nodes ± swollen. Leaf: generally basal and cauline, alternate, petioled except uppermost cauline; ocreae deciduous to persistent. Inflorescence: axillary or generally terminal, generally panicle-like. Flower: generally bisexual, bell-shaped, glabrous, green, ± pink, or red; perianth lobes 6, persistent, in fruit outer 3 ± inconspicuous, inner 3 enlarged, hardened, ± veiny, covering fruit, midrib of 1–3 often expanded into tubercle; stamens 6; stigmas 3, fringed. Fruit: achene, glabrous, ± black or dark brown to ± red.
190–200 species: ± worldwide, 63 in North America. (Latin: sorrel) Mature inner perianth lobes generally needed for identification. Species often hybridize.

Key to Rumex

1. Flowers unisexual, on different plants (some flowers bisexual); leaf blade hastate or sagittate or base tapered; pedicels generally jointed

2. Pedicels jointed distally; inner perianth lobes generally 1.2–1.7(2) mm, ± = fruit; leaf blade widely tapered or generally hastate or sagittate; from a creeping rhizome and/or vertical taproot; California Floristic Province, Great Basin Floristic Province ..... R. acetosella

2' Pedicels jointed near middle or proximally; inner perianth lobes 2.8–3.8 mm, > fruit; leaf blade base tapered; from a vertical taproot and densely tufted underground stolons; High Cascade Range, High Sierra Nevada, Modoc Plateau, White and Inyo Mountains ..... R. paucifolius

1' Flowers generally bisexual, sometimes also unisexual in 1 inflorescence; leaf blades not hastate or sagittate; pedicels jointed or not

3. Leaves cauline; stems decumbent to erect, generally with leafy axillary shoots below terminal inflorescence; leaf blade base tapered to ± rounded; inner perianth margins generally entire (irregularly minutely notched, toothed)

4. Inner perianth lobes (20)23–30 mm wide; Modoc Plateau ..... R. venosus

4' Inner perianth lobes generally < 15 mm wide; Modoc Plateau, elsewhere

5. Perianth tubercles generally 0

6. Inner perianth lobe margin generally minute-toothed; inflorescence ± open; stems ascending (decumbent or ± erect); California (especially mtns, coast) ..... R. californicus

6' Inner perianth lobe margin generally entire; inflorescence dense; stems ascending or generally erect; c&s High Sierra Nevada, expected elsewhere ..... R. utahensis

5' Perianth tubercles >= 1

7. Perianth tubercle width < 1/3 inner lobe, if tubercle 1 then width >= 1/2 lobe

8. Plant terrestrial, submersed, or floating; taproot vertical or creeping; inner perianth lobes 2–2.5(3) mm, 1–1.5(2) mm wide, generally ovate or elliptic; leaf lanceolate to lance-ovate, generally 3.5–5 × longer than wide; Great Basin Floristic Province ..... R. lacustris

8' Plant terrestrial; taproot vertical; inner perianth lobes (2)2.5–3.5(4) mm, (2)2.5–3(3.5) mm wide, widely triangular; leaf linear to lanceolate, generally 5–6 × longer than wide; High Cascade Range, Sierra Nevada, Sacramento Valley (Sutter Buttes), San Gabriel Mountains, Great Basin Floristic Province ..... R. triangulivalvis

7' Perianth tubercle nearly as wide as inner lobe on at least 1 lobe

9. Leaf blade thick, leathery, lance-ovate to -elliptic or ovate-elliptic, <= 3.5 × as long as wide; inner perianth lobes (3)4–5 mm, (2.5)3–4 mm wide; perianth tubercle 1 ..... R. crassus

9' Leaf blade thick or generally thin, occasionally ± leathery, linear to lanceolate, generally > 3.5 × as long as wide; inner perianth lobes generally 2–4 mm, generally 1.5–3 mm wide; perianth tubercles 1 or 3

10. Inner perianth lobes (1.8)2–2.5(3) mm, tubercle 1, smooth to ± warty ..... R. salicifolius

10' Inner perianth lobes (2.5)3–4 mm, tubercles (1)3, generally smooth ..... R. transitorius

3' Leaves basal and cauline (basal often withered when fruit mature); stem generally ± erect, generally unbranched below inflorescence; leaf blade base tapered to cordate; inner perianth margins entire or variously dentate

11. Perianth tubercles 0 or inconspicuous

12. Inner perianth lobes 11–16 mm; ocreae persistent; roots tuber-like ..... R. hymenosepalus

12' Inner perianth lobes 5–10(12) mm; ocreae deciduous to partly persistent; roots not tuber-like ..... R. occidentalis

11' Perianth tubercles 1–3, conspicuous

13. Inner perianth lobe margin generally entire (if toothed or notched, teeth or notches < 0.3 mm)

14. Inner perianth lobe 2–3.5(4) mm, tubercle >= 1/3 its width; inflorescence ± open

15. Perennial herb; perianth tubercles ± equal, almost as wide as lobe ..... R. conglomeratus

15' Annual; perianth tubercles generally unequal, width ± 1/3 lobe ..... R. violascens (2)

14' Inner perianth lobe 3.5–7(7.5) mm, tubercle generally << 1/3 its width; inflorescence generally dense

16. Leaf blade 20–55(70) cm, margins flat to ± wavy; inner perianth lobe 4–7(7.5) mm; pedicel 5–13 mm, joint ±0; stem 8–15(20) dm ..... R. britannica

16' Leaf blade 15–30(35) cm, margin strongly wavy; inner perianth lobe 3.5–6 mm; pedicel (3)4–8 mm, joint swollen; stem 4–10(15) dm ..... R. crispus

13' Inner perianth lobe margin variously dentate, at least some teeth >= 0.3 mm

17. Annual, biennial

18. Inner perianth lobe 3–5.5(6) mm, teeth 1–3(5) mm ..... R. dentatus

18' Inner perianth lobe generally 1.5–3.5 mm, teeth 0.5–4 mm

19. Widest inner perianth lobe narrow-triangular or -kite-shaped, teeth 1–3 mm; inflorescence dense, bracts leaf-like

20. Perianth tubercle straw-colored, oblong-ovate, nearly as wide as inner lobe, tip obtuse; inner perianth lobe teeth ± = width of lobe ..... R. persicarioides

20' Perianth tubercle ± brown or ± red, lance-linear to fusiform, <= 1/2 width of inner lobe, tip ± acute; inner perianth lobe teeth generally 1.5–2.5(4) × width of lobe ..... R. fueginus

19' Widest inner perianth lobe widely ovate-triangular to ± deltate, teeth <= 0.5 mm; inflorescence ± open, bracts ± not leaf-like ..... R. violascens (2)

17' Perennial herb

21. Leaf blade 20–40 cm, widely ovate to oblong, base generally cordate; inner perianth lobe triangular to narrowly ovate-triangular ..... R. obtusifolius

21' Leaf blade 4–25(30) cm, generally oblong to lanceolate, base generally truncate or tapered; inner perianth lobe widely ovate-triangular to round-cordate

22. Inflorescence branches spreading; teeth of inner perianth lobe not wider at base, 0.3–2.5 mm ..... R. pulcher

22' Inflorescence branches ascending; teeth of inner perianth lobe wider at base, 0.2–1.5 mm

23. Inner perianth lobe 6–8(9) mm, round, base generally cordate, teeth 0.2–0.5 mm, each much wider at base ..... R. kerneri

23' Inner perianth lobe 3.5–5 mm, round- to triangular-ovate, base truncate or ± cordate, teeth 0.2–1.5 mm, each ± wider at base ..... R. stenophyllus


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [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].
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