FNA: Juncus dubius vs. Juncus subg. Septati

Phenology

Fruiting early summer–late fall.

Habitat

Montane meadows, riverbeds, canyons, aroyos

Elevation

100–1600 m (300–5200 ft)

Distribution

CA

[WildflowerSearch map]

[BONAP county map]

Worldwide

Discussion

Juncus dubius has rugulose stems and leaves throughout most of its range, but on the periphery (in Mariposa, San Diego, and Sonoma counties, California) the plants are smooth.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species ca. 80 (32 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key

1. Seeds tailed, 0.7–2.6 mm, including tails; seed body covered with whitish translucent veil.	→ 2
1. Seeds not tailed, 0.3–0.7 mm; seed body clear yellow-brown.	→ 7
2. Seeds 1.8–2.6 mm, including tails; stamens usually 6.	→ 3
2. Seeds 0.7–1.9 mm, including tails; stamens usually 3.	→ 4
3. Stems and leaves scabrous; auricles 1–7.5 mm	J. caesariensis
3. Stems and leaves smooth; auricles 0.2–0.4 mm	J. trigonocarpus
4. Seeds 1.1–1.9 mm; heads 5–50-flowered; inflorescence branches erect to ascending	J. canadensis
4. Seeds 0.7–1.2 mm; heads 2–8-flowered or if to 20-flowered then proximal inflorescence branches widely spreading (J. subcaudatus).	→ 5
5. Outer tepals obtuse to nearly acute	J. brachycephalus
5. Outer tepals acuminate to acute.	→ 6
6. Proximal inflorescence branches widely spreading	J. subcaudatus
6. Proximal inflorescence branches erect	J. brevicaudatus
7. Flowers 1–2(–4) at each node, not in heads; capsules fertile only below middle.	→ 8
7. Flowers in heads of 3–60; capsules fertile throughout or only below middle.	→ 9
8. Culms erect, 0.3–7 dm, not forming mats	J. pelocarpus
8. Culms decumbent, 0.1–1 dm, forming mats	J. subtilis
9. Heads spheric or nearly spheric, 15–60-flowered	→ 10
9. Heads obconic to hemispheric, 3–15-flowered.	→ 23
10. Stamens 6.	→ 18
10. Stamens 3.	→ 11
11. Plants cespitose; tepals lanceolate	J. acuminatus
11. Plants rhizomatous; tepals lance-subulate.	→ 12
12. Capsules included	J. brachycarpus
12. Capsule exserted to slightly included.	→ 13
13. Capsules remaining united at apex after dehiscence.	→ 14
13. Capsule valves separating at apex during dehiscence.	→ 16
14. Leaves laterally compressed, 3–5 mm diam.	J. validus var. fascinatus
14. Leaves terete, 1–4 mm diam.	→ 15
15. Heads sometimes spheric, usually lobed; tepals green to stramineous, nearly equal; uppermost cauline leaf blade (below inflorescence bract) equaling or longer than its sheath	J. scirpoides
15. Heads spheric; stramineous to reddish brown, inner tepals shorter than outer; uppermost cauline leaf blade much shorter than its sheath	J. megacephalus
16. Tepals 4–5 mm; leaves laterally compressed	J. validus var. validus
16. Tepals 2.9–4 mm; leaves terete.	→ 17
17. Capsules 3.5–5 mm, exserted; culms 0.4–3 dm	J. nodosus
17. Capsules 3–3.5 mm; equaling perianth or slightly shorter; culms 2.5–8.5 dm	J. bolanderi
18. Tepals lanceolate to lance-ovate, light green to light pink or white or dark purplish brown; capsule ovoid to obovoid, 1.9–3.5 mm; heads 1–2 per inflorescence (15–50 for J. pervetus).	→ 19
18. Tepals lance-subulate, green to stramineous; capsule lance-subulate, 3.2–6.5 mm; heads 1–23 per inflorescence.	→ 21
19. Heads 15–50	J. pervetus
19. Heads 1–2.	→ 20
20. Tepals dark purplish brown to black; anthers 1/4 to equal filament length	J. mertensianus
20. Tepals light green, or light pink to white; anthers 2–3 times length of filaments	J. chlorocephalus
21. Outer tepals 2.4–4.1 mm, equaling inner tepals; auricles 0.5–1.7 mm	J. nodosus
21. Outer tepals 4–6 mm, outer and inner tepals unequal in length; auricles 1–4 mm.	→ 22
22. Outer tepals longer than inner; capsule 4.3–5.7 mm	J. torreyi
22. Outer tepals shorter than inner; capsules 5.2–6.5 mm	J. texanus
23. Stamens 3.	→ 24
23. Stamens 6.	→ 31
24. Stems creeping or floating, capillary; filiform, submersed leaves often formed before flowering; inflorescences with 1–9 heads.	→ 25
24. Stems erect, not floating; filiform leaves absent; inflorescences with 3–200 heads.	→ 26
25. Capsule rounded at apex, 2.5–4 mm; tepals 2–3.6 mm, obtuse to acute	J. bulbosus
25. Capsule acute to acuminate at apex, 3.5–6.1 mm; tepals 2.8–5.5 mm, acute to acuminate-subulate	J. supiniformis
26. Capsule much longer than perianth, 1.3–2 times perianth length.	→ 27
26. Capsule equaling or just exceeding perianth.	→ 29
27. Capsules beaked; plants often decumbent or matted	J. supiniformis
27. Capsules not beaked; plants erect.	→ 28
28. Capsule 1/3 longer than perianth, 2.8–4.2 mm	J. debilis
28. Capsule twice as long as perianth, 4–5.2 mm	J. diffusissimus
29. Heads 5–50; tepals 2.6–3.5 mm, nearly equal; capsules 2.8–3.5 mm	J. acuminatus
29. Heads 30–250; tepals 1.7–2.9 mm, inner tepals shorter than outer tepals; capsules 1.9–2.9 mm.	→ 30
30. Leaf blade with prominent and conspicuous ringlike bands at position of cross partitions; roots without terminal tubers; inner tepals 1.7–2.1 mm	J. nodatus
30. Leaf blade with faint ringlike bands at position of septa; roots often with terminal tubers; inner tepals 2.4–2.8 mm	J. elliottii
31. Stems creeping or floating, capillary; filiform, submersed leaves often formed before flowering; inflorescences with 1–9 heads.	→ 32
31. Stems erect; filiform submersed leaves not formed except in J. militaris; heads 1–66.	→ 34
32. Auricles 0.8–2.1 mm; capsules 3.5–6.1 mm	J. supiniformis
32. Auricles 0.4–1 mm; capsules 2.5–4 mm.	→ 33
33. Capsules exserted about 1 mm beyond perianth; apex acute below beak; outer tepals acute to acuminate	J. articulatus
33. Capsules as long as tepals or exserted to 0.5 mm beyond tepals, apex obtuse below apex; outer tepals acute to obtuse	J. bulbosus
34. Proximal culm leaf overtopping inflorescences, distal culm leaf usually inflated, bladeless sheath; often developing filiform (hairlike) leaves off rhizome in running water	J. militaris
34. Proximal culm leaf shorter than inflorescence, distal culm leaf usually with blade, sheath not inflated; not developing filiform leaves off rhizome.	→ 35
35. Tepals 1.6–3 mm; apex obtuse to acuminate, usually not subulate mucronate; anthers shorter than to equaling filaments.	→ 36
35. Tepals 2.3–6.2 mm; apex usually acuminate with subulate mucro (acute in J. acutiflorus); anthers equaling or longer than filaments.	→ 37
36. Inner tepals obtuse; inflorescence stiffly erect	J. alpinoarticulatus
36. Inner tepals acuminate; inflorescence spreading	J. articulatus
37. Capsule abruptly contracted at apex, usually not exserted	J. nevadensis
37. Capsule narrowed to beak, exserted at least slightly.	→ 38
38. Heads 2–9; tepals 2.8–5.5 mm	J. supiniformis
38. Heads 25–66; tepals 2.5–3.5 mm.	→ 39
39. Tepals nearly equal; heads with 6–10 flowers	J. dubius
39. Tepals unequal, outer shorter than inner; heads with 5–8 flowers	J. acutiflorus