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Mertens' rush

Habit Herbs, perennial, rhizomatous to cespitose, 0.5–4 dm.
Rhizomes

1–2 mm diam., not swollen.

Culms

erect, terete, 1–3 mm diam., smooth.

Cataphylls

0–1, straw-colored to chestnut brown, apex acute.

Leaves

basal 1–2, cauline 0–1;

auricles 1–1.2 mm, apex rounded to acute, membranaceous or scarious;

blade green to straw-colored, terete, 3–15 cm × 0.3–0.6 mm.

Inflorescences

terminal single head (rarely cluster of 2 heads), 0.5–1.6 cm;

primary bract erect;

heads 12–60-flowered, spheric (to hemispheric), 4.5–15 mm diam.

Flowers

tepals dark purplish brown to black, lanceolate to lance-ovate, apex acute, mucro subulate;

outer tepals 2.4–4.9 mm;

inner tepals 2.3–4.3 mm;

stamens 6, anthers 1/4 to equal filament length.

Capsules

included or slightly exserted, chestnut brown, 1-locular, obovoid, 1.9–3.5 mm, apex obtuse or rounded, valves separating at dehiscence, fertile throughout or only proximal to middle.

Seeds

ellipsoid, 0.4–0.5 mm, not tailed;

body clear yellow-brown.

2n

= 40.

Juncus mertensianus

Phenology Fruiting mid summer–fall.
Habitat Montane to alpine meadows, stream banks, lake margins, and conifer woods
Elevation (400–)1900–3300 m ((1300–)6200–10800 ft)
Distribution
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; NT; SK; YT
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[BONAP county map]
Discussion

Populations from southern California with brown tepals, anthers equaling filaments, and rounded to acute, translucent auricles have been separated as Juncus duranii; the typical form is so highly variable, however, that it can easily accommodate this local form. This species passes into Juncus nevadensis and has often been combined with that species (F. J. Hermann 1964). The two species can generally be separated, and we are following those treatments (F. J. Hermann 1975; A. Cronquist et al. 1972+, vol. 6).

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

Source FNA vol. 22, p. 252.
Parent taxa Juncaceae > Juncus > subg. Septati
Sibling taxa
J. acuminatus, J. acutiflorus, J. acutus, J. alpinoarticulatus, J. anthelatus, J. arcticus, J. articulatus, J. biglumis, J. bolanderi, J. brachycarpus, J. brachycephalus, J. brachyphyllus, J. brevicaudatus, J. bryoides, J. bufonius, J. bulbosus, J. caesariensis, J. canadensis, J. capillaris, J. capitatus, J. castaneus, J. chlorocephalus, J. compressus, J. confusus, J. cooperi, J. coriaceus, J. covillei, J. debilis, J. dichotomus, J. diffusissimus, J. drummondii, J. dubius, J. dudleyi, J. effusus, J. elliottii, J. ensifolius, J. falcatus, J. filiformis, J. filipendulus, J. georgianus, J. gerardii, J. greenei, J. gymnocarpus, J. hallii, J. hemiendytus, J. howellii, J. inflexus, J. interior, J. kelloggii, J. leiospermus, J. lesueurii, J. longistylis, J. luciensis, J. macrandrus, J. macrophyllus, J. marginatus, J. maritimus, J. megacephalus, J. militaris, J. nevadensis, J. nodatus, J. nodosus, J. occidentalis, J. orthophyllus, J. oxymeris, J. parryi, J. patens, J. pelocarpus, J. pervetus, J. phaeocephalus, J. polycephalus, J. regelii, J. repens, J. roemerianus, J. scirpoides, J. secundus, J. squarrosus, J. stygius, J. subcaudatus, J. subtilis, J. supiniformis, J. tenuis, J. texanus, J. textilis, J. tiehmii, J. torreyi, J. trifidus, J. triformis, J. triglumis, J. trigonocarpus, J. uncialis, J. validus, J. vaseyi, J. xiphioides
Synonyms J. duranii, J. mertensianus var. duranii, J. mertensianus var. filifolius, J. slwookoorum
Name authority Bongard: Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 167. (1833)
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