Jepson eFlora
Key to families | Table of families and genera

Key to Juncus

View taxon page for Juncus

Key to Groups

1. Annual generally < 10 cm; roots fine, fibrous; leaves narrow, generally inrolled, generally < 1 mm wide ..... Group 1

1' Perennial herb; plant generally larger in all respects; roots coarse or rhizomes present; leaves narrow or wide, inrolled to flat or cylindric

2. Inflorescence bract cylindric, resembling continuation of stem; inflorescence appearing lateral ..... Group 2

2' Inflorescence bract not cylindric, not resembling continuation of stem, or if so then channeled along inner side; inflorescence appearing terminal

3. Leaf blade generally cylindric or nearly so; crosswalls generally complete ..... Group 3

3' Leaf blade flat or wiry; crosswalls incomplete or 0

4. Leaf blade iris-like, flattened, oriented with edge toward stem (at least from middle to tip), crosswalls generally incomplete ..... Group 4

4' Leaf blade wiry or grass-like, if flattened then oriented with flat side toward stem, crosswalls 0

5. 2 bractlets subtending flower; leaves slender, generally < 1.3 mm wide, generally wiry or channeled; flowers 1 or in clusters ..... Group 5

5' 1 bractlet subtending flower; leaves broader, generally 2–7 mm wide, flat; flowers in clusters ..... Group 6

Group 1: Annual

1. Stem generally branched, leafy; inflorescence or flowers scattered along stem or congested in terminal cluster; stamens 3 or 6

2. Sepals 2–4 mm

3. Flowers scattered along stem, 1 per node ..... J. bufonius var. occidentalis

3' Flowers terminal, 3–10(25) per cluster

4. Perianth green to red or pale brown; lowest bract > inflorescence ..... J. capitatus (2)

4' Perianth dark brown to ± black; lowest bract < inflorescence ..... J. planifolius

2' Sepals generally 4–10 mm

5. Fruit tip generally truncate, ± = petals; petals ± blunt ..... J. ambiguus

5' Fruit tip generally rounded or acute, < petals; petals acute to acuminate

6. Inflorescence open; generally non-saline soil ..... J. bufonius var. bufonius

6' Inflorescence congested, dense; generally saline soil ..... J. bufonius var. congestus

1' Stem not branched, leafless, leaves basal; inflorescence or flowers terminal; stamens 2–3(5)

7. Inflorescence bracts leaf-like, > inflorescence; sepals >>, more acuminate than petals ..... J. capitatus (2)

7' Inflorescence bracts inconspicuous, membranous, < inflorescence; sepals, petals similar in size, shape, occasionally sepals < petals

8. Anthers >= 0.9 mm, >(=) filaments; style >= 0.9 mm, flowers outcrossing

9. Fruit generally 11–17 mm, ± 3–4 × > perianth ..... J. digitatus

9' Fruit 1–5 mm, < or ± = perianth

10. Perianth parts acuminate; petals colored to tip, margins narrowly scarious; seed striate at 15× ..... J. triformis

10' Perianth parts acute; petals generally not colored to tip, sepal and petal margins broadly scarious; seed not striate at 15× ..... J. leiospermus

11. Flowers generally 1(2) per stem ..... var. ahartii

11' Flowers generally 2–4(7) per stem ..... var. leiospermus

8' Anthers < 0.8 mm, < filaments; style < 0.6 mm, flowers generally self-pollinating

12. Perianth dark brown to ± black; generally 3–6+ flowers per stem ..... J. planifolius (2)

12' Perianth generally green to pink or red; generally 1–2 flowers per stem

13. Seed not striate; flowers 1 per stem; bracts 0 or 1–2, truncate to acute

14. Inflorescence bractlets 0; stem thickened below flower ..... J. hemiendytus var. abjectus

14' Inflorescence bractlets 1–2; stem not thickened below flower

15. Inflorescence bractlet 1, tip truncate, sheathing stem; stamens 2–3 ..... J. uncialis

15' Inflorescence bractlets 1–2, tips acute to blunt, ovate to rounded, not sheathing stem; stamens 2–4

16. Perianth parts generally 6, shiny, incurved, generally > fruit ..... J. bryoides

16' Perianth parts generally 4, dull, erect or outcurved, generally < fruit ..... J. hemiendytus var. hemiendytus

13' Seed striate; flowers 1–2(7) per stem; bracts 2, acute to acuminate

17. Perianth parts generally 4

18. Fruit much paler than perianth; seed 0.5–0.8 mm, < 4 per row, < 10 per capsule; fruit generally ± spheric to obovoid, < perianth ..... J. capillaris (2)

18' Fruit, perianth both pale green or pink; seed 0.3–0.5 mm, > 4 per row, > 10 per capsule; some fruit ± ellipsoid or oblong, >= perianth ..... J. tiehmii

17' Perianth parts generally 6

19. Perianth generally > and darker than capsule; < 10 seeds per capsule; seed 0.5–0.8 mm, striations generally faint at 30× ..... J. capillaris (2)

19' Perianth ± = and same color as capsule; > 40 seeds per capsule; seed 0.3–0.6 mm, striations obvious at 30×

20. Flowers generally (1)2–3(4) per stem; fruit, perianth generally ± dark red in age; seed 0.4–0.6 mm ..... J. kelloggii

20' Flowers 1(2) per stem; fruit, perianth generally pale green to pale red in age, perianth midvein tips dark red; seed 0.3–0.4 mm ..... J. luciensis

Group 2: Perennial herb; inflorescence bract erect and stem-like

1. Rhizomes long, creeping; stem scattered or in lines, in loose colonies

2. Blades well developed on some upper sheaths, > 5 cm, stem-like ..... J. mexicanus

2' Blades 0 or < 1 cm, not stem-like

3. Perianth < 5.5(6) mm; inflorescence open

4. Stem smooth, not stiff, generally dark green; fruit acute below beak; stem generally < 1.1 m ..... J. balticus subsp. ater

4' Stem ridged, stiff, gray-green; fruit ± obtuse below beak; stem to 2 m ..... J. textilis

3' Perianth generally > 6 mm; inflorescence open or a dense head

5. Inflorescence dense, branches obscured; older sheaths shiny, dark brown; stem generally flattened, generally arching, twisted ..... J. breweri

5' Inflorescence generally open, branches obvious; sheaths dull to ± shiny, pale to dark brown; stem cylindric, erect, generally not twisted ..... J. lescurii

1' Rhizomes short; stem cespitose, in dense tufts like bunchgrass

6. Stamens 6

7. Inflorescence < 6 flowers

8. Fruit notched or truncate; leaf blades 0 or vestigial; moist ground ..... J. drummondii

8' Fruit acute or acuminate; leaf blades > 2 cm, stem-like; ± dry ground ..... J. parryi

7' Inflorescence > 10 flowers

9. Sheaths bladeless; stem slender, blue-green ..... J. patens

9' Sheaths with blades 5–100 cm, stem-like, tip sharp; stem coarse, dark green

10. Perianth 2–4 mm; fruit >> perianth; fresh sepals rounded or notched with short awn, thin, not stiff; stem smooth, base fibrous ..... J. acutus subsp. leopoldii

10' Perianth 4–6 mm; fruit ± = perianth; fresh sepals spiny, acuminate, thick, firm; stem with 6–11 low wide ridges per side, base not fibrous ..... J. cooperi

6' Stamens 3

11. Petals blunt, perianth << fruit; pith generally chambered ..... J. usitatus

11' Petals acuminate, perianth ± >= fruit; pith generally solid

12. Upper sheath tip generally strongly asymmetrical on fertile stem

13. Sheath tip thickened, with a raised rim; sheath generally dark brown to black ..... J. effusus subsp. pacificus

13' Sheath tip thin with broad membranous wings; sheath green when fresh to pale or mid-brown when dry

14. Perianth dark brown- to black-striped; fertile stem slender, generally 0.8–2 mm diam above sheath; North Coast, Klamath Ranges, Central Coast, Outer South Coast Ranges ..... J. hesperius

14' Perianth pale brown; fertile stem stout, generally 2–3.7 mm diam above sheath; Southwestern California, Sonoran Desert ..... J. effusus subsp. austrocalifornicus

12' Upper sheath tip ± symmetrical on fertile stem

15. Fertile stem slender, 0.8–2 mm diam above sheath; perianth with mid- to dark-brown stripes; stem striations 8–12 per side, coarse, best seen on dry stem; montane natives

16. Upper 1/2 of sheath green to pale brown, thin, dull, veins prominent, tip thin, ± inrolled towards stem ..... J. exiguus

16' Sheath generally dark brown to ± black throughout, thick, glossy, veins obscure, tip thickened, not inrolled ..... J. laccatus

15' Fertile stem stout, generally 2–5 mm diam above sheath; perianth generally pale brown; stem striations 14–26 per side, slender; rare introduced subspecies ..... J. effusus

17. Perianth spreading or curving away from fruit; sheaths 5–14 cm, margins generally dark-banded; sheath clasping stem, margins overlapping 2–4 cm from tip ..... subsp. effusus

17' Perianth erect, pressed to fruit; sheaths generally 15–27 cm, margins generally pale; sheath not clasping stem, margins generally loose, flattened or unrolled ..... subsp. solutus

Group 3: Perennial herb; leaf blades with regular crosswalls, generally tubular, scarcely flattened

1. Plant matted, submerged, early leaves hair-like; stem capillary

2. Fruit tip blunt or truncate, 2–3.5 mm; sepals >= petals; petal tips blunt ..... J. bulbosus (2)

2' Fruit tip acute or acuminate, 3.5–6.1 mm; sepals <= petals; petal tips acute to acuminate ..... J. supiniformis (3)

1' Plant not matted, generally not submerged; leaves and stem generally wider

3. Most or all flowers with 3 stamens

4. Plant long-rhizomatous; inflorescence dense, clusters 1–3(5), > 20-flowered ..... J. bolanderi

4' Plant cespitose; inflorescence open, clusters > 5, < 15–flowered

5. Fruit generally <= perianth

6. Root tubers 0; perianth >= 2.6 mm; fruit > 2.5 mm ..... J. acuminatus

6' Roots with some oblong tubers near tips; perianth <= 2.5 mm; fruit < 2.3 mm ..... J. elliottii

5' Fruit > perianth

7. Perianth 3.4–5.4 mm; inflorescence bulblets occasionally present; fruit dark ..... J. supiniformis (3)

7' Perianth 2.3–3.2 mm; inflorescence bulblets 0; fruit pale ..... J. diffusissimus

3' Most or all flower with 6 stamens

8. Leaf, stem surfaces conspicuously wrinkled ..... J. rugulosus

8' Leaf, stem surfaces smooth

9. Rhizome nodes tuberous

10. Sepals > petals; inflorescence bracts spreading; fruit ± = perianth; inflorescence clusters generally 1–1.5 cm wide ..... J. torreyi

10' Sepals ± = petals; inflorescence bracts ascending; fruit > perianth; inflorescence clusters generally < 1 cm wide ..... J. nodosus

9' Rhizome tubers 0

11. Anthers > filaments

12. Inflorescence clusters 1–3

13. Perianth white to pink or ± green ..... J. chlorocephalus

13' Perianth ± brown-black ..... J. mertensianus (2)

12' Inflorescence clusters generally > 5

14. Fruit abruptly narrowed to beak; fruit generally <= perianth ..... J. nevadensis var. nevadensis

14' Fruit gradually tapered to beak; fruit generally > perianth

15. Petals generally blunt, tips hooded; fruit generally dark brown to black ..... J. articulatus subsp. articulatus (2)

15' Petals acuminate, bristle-tipped; fruit light brown to red or dark red ..... J. dubius

11' Anthers <= filaments

16. Inflorescence clusters generally > 5; fruit > perianth; inflorescence bulblets occasionally present; stem occasionally rooting at nodes

17. Fruit tip blunt or truncate below style; leaf with >= 1 cylindrical air chamber in ×-section ..... J. bulbosus (2)

17' Fruit tip acute or acuminate below style; leaf with 1 cylindrical air chamber in ×-section

18. Inflorescence clusters > 10; perianth 1.9–3.1 mm; pale petal margins wide, flat, tips generally blunt, hooded ..... J. articulatus subsp. articulatus (2)

18' Inflorescence clusters < 10; perianth 3.4–5.4 mm; pale petal margins narrow, generally inrolled, tips acuminate ..... J. supiniformis (3)

16' Inflorescence clusters generally 1–3; fruit generally <= perianth; inflorescence bulblets 0, stem not rooting at nodes

19. Fruit abruptly tapered to distinct beak; leaves ± to strongly flattened, hollow, blue-green; stem with 1–3(4) heads; n North Coast ..... J. nevadensis var. inventus

19' Fruit generally notched or truncate, ± beakless; leaves tubular, hollow, green; stem with 1(2) heads; montane

20. Perianth generally < 2.8 mm; perianth brown, stiff; inflorescence bract narrow, generally not sheathing; Southwestern California ..... J. duranii

20' Perianth generally > 3.1 mm; perianth ± purple-black, not stiff; inflorescence bract wide, generally sheathing; not Southwestern California ..... J. mertensianus (2)

Group 4: Perennial herb; leaf blades flattened, iris-like, crosswalls generally incomplete

1. Fruit gradually tapered to long beak

2. Perianth green, tips red or purple; inflorescence generally > 15 cm, clusters generally <= 8-flowered ..... J. oxymeris

2' Perianth generally dark brown to dark purple-brown or ± black; inflorescence generally < 10 cm, clusters > 8-flowered ..... J. phaeocephalus

3. Inflorescence 10+ few-flowered clusters; clusters generally 5–10 mm wide ..... var. paniculatus

3' Inflorescence 1–10 many-flowered clusters; clusters generally > 10 mm wide ..... var. phaeocephalus

1' Fruit abruptly tapered to beak

4. Anthers generally 1–1.5 mm, >> filaments; styles >= 1 mm; flowers outcrossing ..... J. macrandrus

4' Anthers 0.5–1 mm, generally <= filaments; styles <= 1 mm; flowers generally self-pollinating

5. Stamens generally 3; perianth generally dark brown to black ..... J. ensifolius

5' Stamens generally 6; perianth generally green to red-tipped or brown

6. Leaves generally 2–5 mm wide; perianth brown ..... J. saximontanus

6' Leaves generally 5–14 mm wide; perianth green, red-tipped ..... J. xiphioides

Group 5: Perennial herb; leaf blades wiry or slightly flattened and channeled, < 1.3 mm wide

1. Perianth black-striped, tips blunt, hooded, incurved; anthers >> filaments; rhizomatous; coastal salt marshes ..... J. gerardi subsp. gerardi

1' Perianth green, brown, or red, tips acute or acuminate, not incurved or hooded; anthers < to > filaments; cespitose; inland wetlands

2. Leaf sheath appendages stiff, thick, plastic-like, rounded, shiny, ± yellow ..... J. dudleyi

2' Leaf sheath appendages not stiff, thin, rounded to acuminate, dull, white or translucent

3. Fruit chambers 3, partitions straight, united except at tip

4. Sepals ± = petals; style 0.1–0.2 mm; anthers < filaments; perianth with thick, darker brown stripes, pale margins broad; inflorescence generally compact ..... J. confusus

4' Sepals > petals; style (0.3)0.4–0.8 mm; anthers > filaments; perianth generally green or light brown, pale margins narrow; inflorescence open ..... J. trilocularis

3' Fruit chamber 1, partitions concave, separated except at base

5. Fruit ridged, truncate or notched; perianth green or with thick dark brown stripes ..... J. occidentalis

5' Fruit ridges 0 or obscure, fruit rounded or acute; perianth green or ± red, pale brown in age

6. Leaf sheath appendages generally rounded, ± opaque below, 0.2–0.6 mm; bractlets acuminate, generally bristle-tipped; stem with 2–6 strong ridges per side

7. Bractlets acute to blunt, not bristle-tipped; inflorescence bracts ± hardened; seed 0.3–0.4 mm; Inner North Coast Ranges ..... J. dichotomus

7' Bractlets acuminate, generally bristle-tipped; inflorescence bracts soft; seed 0.4–0.7 mm; Desert Mountains ..... J. interior

6' Leaf sheath appendages generally acute to acuminate, ± translucent, generally 1–8 mm until late in season when generally smaller or absent; bractlets generally acute to blunt; stem with or without strong ridges per side; widespread

8. Stem with 2–6 strong ridges per side; fruit < 2.5 mm, < 75% perianth; inflorescence generally orange-red; flower < internodes ..... [J. anthelatus]

8' Stem with 0–1 strong ridges per side; fruit generally > 2.5 mm, > 75% perianth; inflorescence generally green; flower generally > internodes ..... J. tenuis

Group 6: Perennial herb; leaf blades flattened, grass-like, generally 2–7 mm wide

1. Stamens 3

2. Plant base with knobby tubers; anthers ± purple-red; cespitose ..... J. marginatus

2' Tubers 0; anthers yellow; rhizomatous or cespitose ..... J. planifolius

1' Stamens 6

3. Seeds slender, 1–2 appendages >= 1/2 seed body

4. Seed body > both appendages; petals generally > sepals; inflorescence clusters generally 5–20, clusters generally 2–5-flowered; leaves <= 4.5 mm wide ..... J. howellii

4' Seed body < 1–2 appendages; petals generally = sepals; inflorescence clusters 1–5, clusters generally 10–30-flowered; leaves < 3 mm wide ..... J. regelii

3' Seeds plump, appendages 0 or short points, << seed body

5. Perianth generally 2–3.6 mm; fruit >= perianth

6. Fruit blunt or notched, petals blunt or acute; heads 1–6, branches erect, inflorescence narrow; leaves blue-green ..... J. covillei

6' Fruit, petals acuminate; heads 10–50, branches spreading, inflorescence diffuse; leaves green ..... J. cyperoides

5' Perianth generally 4–6 mm; fruit generally <= perianth

7. Leaf sheath appendages well developed, generally rounded, > 1 mm

8. Rhizomatous; sepals generally = petals; inflorescence clusters 1–4(5); perianth midveins smooth to occasionally papillate, green ..... J. longistylis

8' Loosely cespitose; sepals < petals; inflorescence clusters 8–30; perianth midveins smooth, generally red-streaked ..... J. macrophyllus

7' Leaf sheath appendages 0 or obscure, generally pointed, < 1 mm

9. Perianth parts < 1.5 mm wide; fruit brown; heads 3–12; generally montane ..... J. orthophyllus

9' Perianth parts > 1.5 mm wide; fruit ± black; heads 1–3(5); coastal ..... J. falcatus

10. Petals acuminate, generally > 5 mm; anthers generally > 1.7; fruit tip acute to truncate, inconspicuous, << perianth, generally ellipsoid to oblong; Central Coast ..... subsp. falcatus

10' Petals acute to blunt, generally < 4.5 mm; anthers < 1.5 mm; fruit tip notched, conspicuous, ± = perianth, generally spheric to broadly ellipsoid; North Coast ..... subsp. sitchensis

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