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thread rush

iris-leaf rush

Habit Herbs, perennial, 0.2–3.5 dm. Herbs, perennial, rhizomatous, 5–9 dm.
Rhizomes

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

2–3 mm diam.

Culms

terete, 1 mm diam.

erect, 2–6 mm diam.

Cataphylls

several.

0 or 1–2, straw-colored, apex narrowly acute.

Leaves

blade absent.

basal 1–3, cauline 2–6, straw-colored;

auricles absent;

blade 10–40 cm x (3–)7–12 mm.

Inflorescences

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

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

panicles or racemes of 20–50 heads, 2–14 cm, erect or ascending branches;

primary bract erect;

heads 15–70-flowered, obovoid to globose, 7–11 mm diam.

Flowers

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.

tepals green to brown or reddish brown, lanceolate, 2.4–3.7 mm, nearly equal, apex acuminate;

stamens 6;

anthers ½1/2 to equal filament length.

Capsules

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

slightly exserted, chestnut to dark brown, 1-locular, ellipsoid, 2.4–3.8 mm, apex acuminate, not beaked.

Seeds

amber, 0.5–0.6 mm, not tailed.

elliptic to obovate, 0.4–0.6 mm, not tailed.

2n

= 40, 70, 80, 84.

= 40.

Juncus filiformis

Juncus xiphioides

Phenology Flowering and fruiting summer. Fruiting early summer–fall.
Habitat Usually sandy, moist or wet soil along stream banks, pools, lakes or in meadow depressions, rarely in bogs, frequently hidden by larger vegetation Salt marshes, moist areas, ditches, springs, lake and stream shores
Elevation 0–3000 m (0–9800 ft) 500–1600 m (1600–5200 ft)
Distribution
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]
from FNA
AZ; CA; NM; NV; UT; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
Discussion

This species and the next (Juncus ensifolius) are closely related and have been treated as members of a single species (J. xiphioides) by Engelmann. Until a study of the complete subgenus is done, we are hesitant to use a varietal name (J. xiphioides var. triandrus) for the widespread western taxon J. ensifolius.

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

Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Genuini Juncaceae > Juncus > subg. Ensifolii
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. 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. 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
Synonyms J. xiphioides var. auratus, J. xiphioides var. littoralis
Name authority Linnaeus: Sp. Pl. 1: 326. (1753) E. Meyer: Synopsis Juncorum 50. (1822)
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