Juncus dubius

Engelmann

2:459. 1868.

Endemic
Synonyms: Juncus rugulosus Engelmann
Treatment appears in FNA Volume 22.

Herbs, perennial, rhizomatous, 3–7.5 dm. Rhizomes 2–3 mm diam., not swollen. Culms erect, terete, 2–4 mm diam., smooth or rugulose. Cataphylls 1–2, pink to straw-colored, apex acute. Leaves: basal 1–2, cauline 1–2; auricles 1–4.9 mm,, apex rounded, membranaceous; blade green to straw-colored, terete, 20–30 cm × 1.5–4 mm, rugulose or smooth. Inflorescences terminal panicles of 25–66 heads, 7–13 cm, branches spreading; primary bract erect; heads 6–10-flowered, hemispheric to obovoid, 5–10 mm diam. Flowers: tepals straw-colored to brown, lanceolate, apex acuminate; outer tepals (2–) 2.5–3.4 mm; inner tepals (2–) 2.6–3.6 mm; stamens 6, anthers 1.5–2 times filament length. Capsules exserted, chestnut-brown, 1-locular, subuloidsubulate, (2.4–) 3–3.9 mm, apex tapering to subulate tip, valves separating at dehiscence. Seeds obovoid, 0.3–0.4 mm, not tailed. 2n = 40.


Phenology: Fruiting early summer–late fall.
Habitat: Montane meadows, riverbeds, canyons, aroyos
Elevation: 100–1600 m

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.

Selected References

None.

Lower Taxa

None.

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

... more about "Juncus dubius"
persistent +
membranaceous +
0.1 cm1 mm <br />0.001 m <br /> (0.49 cm4.9 mm <br />0.0049 m <br />) +
Ralph E. Brooks* +  and Steven E. Clemants* +
Engelmann +
green +  and straw-colored +
20 cm200 mm <br />0.2 m <br /> (30 cm300 mm <br />0.3 m <br />) +
smooth +  and rugulose +
1.5mm;4mm +
ascending +  and erect +
terete +, involute +  and flat +
0.24 cm2.4 mm <br />0.0024 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
chestnut-brown +
0.3 cm3 mm <br />0.003 m <br /> (0.39 cm3.9 mm <br />0.0039 m <br />) +
pink +  and straw-colored +
rugulose +  and smooth +
100–1600 m +
arranged +  and cluster +
Montane meadows, riverbeds, canyons, aroyos +
6-10-flowered +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
hemispheric +  and obovoid +
pseudoaxillary +  and terminal +
0.2 cm2 mm <br />0.002 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
0.26 cm2.6 mm <br />0.0026 m <br /> (0.36 cm3.6 mm <br />0.0036 m <br />) +
cauline +  and basal +
3 +  and 1 +
0.2 cm2 mm <br />0.002 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.34 cm3.4 mm <br />0.0034 m <br />) +
persistent +
Fruiting early summer–late fall. +
parietal +  and axile +
Abhandlungen herausgegeben vom naturwissenschaftlichen Vereine zu Bremen +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
not swollen +
not tailed;obovoid +
green;brown or purplish black +
persistent +
generally longer +
Juncus rugulosus +
Juncus dubius +
Juncus subg. Septati +
species +
straw-colored +  and brown +
lanceolate +
7 cm70 mm <br />0.07 m <br /> (13 cm130 mm <br />0.13 m <br />) +