Flora of North America species comparison

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Juncus arcticus

Juncus falcatus

arctic rush

falcate rush, sickle-leaf rush
Habit Herbs, perennial, 2–10 dm. Herbs, perennial, rhizomatous, 0.5–3 dm.
Rhizomes

long- creeping.

Culms

erect, 1–3 mm diam.

erect, slightly compressed.
Cataphylls

several.

Leaves

blade usually absent (present in var. mexicanus).

basal 2–4, cauline 1–3;

auricles absent or rudimentary;

blade flat, 4–15 cm × 1.5–3 mm.
Inflorescences

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

primary bract barely exceeding to many times longer than inflorescence.

glomerules, (1–)2–5, each with 2–15 flowers, open or aggregate;

primary bract usually exceeding inflorescence.
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.

tepals brown, ovate-lanceolate, 4.5–6 mm, margins scarious, minutely papillate;

inner series slightly shorter.
Capsules

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

brown, 3-locular, obovoid, 3–5 mm, shorter than perianth.
Seeds

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

ovoid to pyriform, 0.7 mm, not tailed.

Juncus arcticus

Juncus falcatus
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; CA; OR; WA; BC; Pacific Islands
[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.)

Varieties 2 (2 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
1. Filaments much shorter than anthers
var. falcatus
1. Filaments ca. as long as anthers
var. sitchensis
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Genuini Juncaceae > Juncus > subg. Graminifolii
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. 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
Subordinate taxa
J. arcticus var. alaskanus, J. arcticus var. balticus, J. arcticus var. mexicanus
J. falcatus var. falcatus, J. falcatus var. sitchensis
Name authority Willdenow: Sp. Pl. 2: 206. (1799) E. Meyer: Syn. Luzul. 34. (1823)
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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