Flora of North America species comparison

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Juncus effusus

Juncus compressus

common bog rush, common rush, common soft rush, pasture rush, soft or lamp rush, soft rush

compressed rush, round-fruit rush
Habit Herbs, perennial, 4–13 dm. Herbs, perennial, to 8 dm.
Rhizomes

short -branched, forming distinct, often large clumps.

short- creeping or densely branching, if densely branching herb appearing cespitose.
Culms

erect, terete, 1–2.5 mm diam. at top of sheaths.

Cataphylls

several.

1–3.
Leaves

blade absent.

basal and cauline, 1–2;

auricles 0.3–0.5 mm, scarious to membranous;

blade flat to slightly channeled, 5–35 cm × 0.8–2 mm, margins entire.
Inflorescences

lateral, compound dichasia, many flowered;

primary bract erect, terete, extending well beyond dichasium.

5–60-flowered, lax, loose to moderately congested, 1.5–8 cm;

primary bract usually exceeding inflorescence.
Flowers

tepals tan or darker, usually with greenish midstripe, lanceolate, 1.9–3.5 mm;

inner slightly shorter;

stamens 3, filaments 0.5–0.8 mm, anthers 0.5–0.8 mm;

style 0.2 mm.

bracteoles 2;

tepals brownish, ovate to oblong, 1.7–2.7 mm;

inner and outer series nearly equal, apex obtuse;

stamens 6, filaments 0.5–0.7 mm, anthers 0.6–1 mm;

style 0.3 mm.
Capsules

greenish tan or darker, 3-locular, broadly ellipsoid to oblate, 1.5–3.2 mm.

brown or darker, pseudo-3-locular, widely ellipsoid to obovoid, 2.5–3.5 × 1.4–1.8 mm, exceeding tepals.
Seeds

amber, (0.3–)0.4–0.5 mm.

light brown, ellipsoid to lunate, 0.35–0.556 mm, not tailed.
2n

= 40, 42.

= 44.

Juncus effusus

Juncus compressus
Phenology Flowering summer, fruiting summer–fall. Flowering and fruiting late spring–early summer.
Habitat Swamps and their edges, marshes, moist meadows, and moist or saturated soils, often conspicuous in pasture meadows where it is shunned by grazing animals Disturbed ground, especially ditches, along railroads and banks of canals and roadsides, frequently in saline or alkaline soils
Elevation Habitat??; 0–2500 m (Habitat??; 0–8200 ft) 1500–2100 m (4900–6900 ft)
Distribution
from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; NE; NH; NJ; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; WV; BC; MB; NB; NF; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; MD; ME; MI; MN; MT; ND; NE; NY; UT; WI; WY; MB; NF; NS; ON; QC; Europe; w Asia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

The Juncus effusus complex has been variously recognized as containing several species or a single species with numerous infraspecific taxa. Unfortunately, North American treatments have dealt primarily with taxa in either the eastern or western portions of the continent. In considering the continent as a whole, little sense can be made of these treatments. The North American J. effusus complex is one that is in obvious need of modern systematic scrutiny.

(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. Poiophylli
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. 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. 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
Synonyms J. conglomeratus, J. effusus var. brunneus, J. effusus var. caeruleomontanus, J. effusus var. costulatus, J. effusus var. dicipiens, J. effusus var. exiguus, J. effusus var. gracilis, J. effusus var. pylaei, J. effusus var. solutus, J. effusus var. subglomeratus, J. griscomii J. bulbosus, J. supinus
Name authority Linnaeus: Sp. Pl. 1: 326. (1753) Jacquin: Enumeratio Stirpium Pleraumque, quae sponte crescung in agro Vindobonensi 60, 235. (1762)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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