Flora of North America species comparison

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Juncus subg. Juncus

Juncus roemerianus

black needlerush, needle rush, needlegrass rush
Habit Herbs, perennial, rhizomatous. Herbs, perennial, 5–15 dm.
Rhizomes

long, thick, scaly.
Culms

gray-green, 2–5 mm diam.
Stems

terete.

Cataphylls

2–5.
Leaves

basal;

blade terete, not septate.

basal, 1–3;

auricles absent;

blade terete, 40–80 cdm × 1.5–2.5 mm.
Inflorescences

terminal (sometimes appearing lateral) panicles of few to many heads, sympodial;

bracteoles absent proximal to perianth.

sympodial or appearing lateral, glomerules to 150, each with 2–6 perfect or pistillate flowers, congested to open, 4–20 × 5–10 cm;

primary bracts terete, longer than inflorescence.
Flowers

in few-flowered heads.

tepals pale brown, 2.5–3.3 mm, apex acuminate;

outer series acuminate;

inner series slightly shorter, acutish;

stamens 6, sometimes rudimentary, filaments 0.2–0.7 mm, anthers 1.3–2.5 mm;

style 0.3–1 mm.
Capsules

3-locular or pseudo-3-locular.

brown, 3-locular, ovoid to oblate, 1.7–3 × 1.3–1.6 mm, mostly distinctly shorter than perianth, apiculate.
Seeds

usually tailed (not tailed in J. roemerianus).

dark brown, ellipsoid, 0.4–0.6 mm, not tailed.

Juncus subg. Juncus

Juncus roemerianus
Phenology Flowering and fruiting spring–early fall.
Habitat Coastal tidal marshes in dense zonal stands
Distribution
Worldwide; coastal in North America
from FNA
AL; DC; DE; FL; GA; LA; MD; MS; NC; SC; VA; Texas
[WildflowerSearch map]
[BONAP county map]
Discussion

Species 9 (4 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Capsules 3.5–5 mm; plants of sw United States.
→ 2
1. Capsules less than 3.5 mm, shorter than or nearly equal to perianth; plants of ne United States Atlantic Coast.
→ 3
2. Capsules nearly globose, obviously longer than perianth
J. acutus subsp. leopoldii
2. Capsules ellipsoid, nearly equal to or shorter than perianth
J. cooperi
3. Capsules nearly equal to perianth; seeds tailed
J. maritimus
3. Capsules distinctly shorter than perianth; seed not tailed
J. roemerianus
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus Juncaceae > Juncus > subg. Juncus
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. 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. 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. acutus subsp. leopoldii, J. cooperi, J. maritimus, J. roemerianus
Synonyms J. section Acuti, J. section Juncastrum, J. section Maritimi, J. section Thalassii, J. subg. Juncastrum, J. subg. Thalassii
Name authority unknown Scheele: Linnaea 22:348. (1849)
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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