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arctic rush

thread rush

Habit Herbs, perennial, 2–10 dm. Herbs, perennial, 0.2–3.5 dm.
Rhizomes

long- creeping.

widely creeping, sparingly branched, 1.5–2 mm diam., nodes closely set.

Culms

erect, 1–3 mm diam.

terete, 1 mm diam.

Cataphylls

several.

several.

Leaves

blade usually absent (present in var. mexicanus).

blade absent.

Inflorescences

lateral, 3–many-flowered, loose to congested;

primary bract barely exceeding to many times longer than inflorescence.

3–10(–12)-flowered, loosely congested, 1–2 cm;

primary bract terete, nearly equaling to much longer than culm.

Flowers

variously pedicellate;

bracteoles membranous;

tepals chestnut brown or paler, lanceolate, (2.5–)3.3–5.5(–6) mm, margins clear;

inner series loosely subtending capsule at maturity; usually slightly shorter, margins scarious to clear, apex acutish to obtuse;

stamens 6, filaments 0.2–1.1 mm, anthers 0.9–2.2 mm;

style 0.9–1.5 mm.

pedicellate;

bracteoles broadly ovate, tepals light brown or green, lanceolate, 2.5–4.2 mm;

inner series loosely subtending capsule at maturity, slightly shorter, margins scarious;

stamens 6, filaments 0.5–0.9 mm, anthers 0.5–0.7 mm;

style 0.2 mm.

Capsules

3-locular or infrequently pseudo-3-locular, oblate to narrowly ovoid, 3.5–4(–4.5) mm, equal to or exceeding perianth.

tan, 3-locular, nearly globose, 2.5–3 × 1.8–2.1 mm, shorter than perianth.

Seeds

dark amber, oblate to ellipsoid, 0.6–0.8 mm.

amber, 0.5–0.6 mm, not tailed.

2n

= 40, 70, 80, 84.

Juncus arcticus

Juncus filiformis

Phenology Flowering and fruiting summer.
Habitat Usually sandy, moist or wet soil along stream banks, pools, lakes or in meadow depressions, rarely in bogs, frequently hidden by larger vegetation
Elevation 0–3000 m (0–9800 ft)
Distribution
from FNA
AK; AR; AZ; CA; CO; DE; IA; ID; IL; IN; KS; MA; MD; ME; MI; MN; MO; MT; ND; NE; NH; NM; NV; NY; OH; OK; OR; PA; SD; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; NU; ON; PE; QC; SK; YT; Mexico; South America; Asia
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CO; ID; MA; ME; MI; MN; MT; NE; NH; NJ; NY; OR; PA; UT; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; SPM; Greenland; Eurasia; Atlantic Islands (Iceland)
[WildflowerSearch map]
[BONAP county map]
Discussion

Numerous entities have been circumscribed and recognized at various nomenclatural ranks by a plethora of authors addressing state or regional floras. In considering the Juncus arcticus-balticus complex as a whole in North America, one is soon confronted with a wide-ranging and obviously polymorphic complex that has not read the literature. It is abundantly clear that the systematics of the group will not be solved on the basis of morphology alone and that resolution of the problem is ripe for molecular investigations.

Varieties 3 7 (3 in the flora).

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

Key
1. Anthers about as long as filaments; blades absent
var. alaskanus
1. Anthers at least 2 times as long as filaments.
→ 2
2. Blade-bearing leaves absent
var. balticus
2. Distal 1 or 2 leaves with obvious blade
var. mexicanus
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Genuini Juncaceae > Juncus > subg. Genuini
Sibling taxa
J. acuminatus, J. acutiflorus, J. acutus, J. alpinoarticulatus, J. anthelatus, 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. mertensianus, 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
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. 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. mertensianus, 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
Subordinate taxa
J. arcticus var. alaskanus, J. arcticus var. balticus, J. arcticus var. mexicanus
Name authority Willdenow: Sp. Pl. 2: 206. (1799) Linnaeus: Sp. Pl. 1: 326. (1753)
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