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small-head rush

hair-leaf rush, hairy-leaf rush, spreading rush

Habit Herbs, perennial, cespitose, 2–7 dm. Herbs, perennial, cespitose or matted, often decumbent, rooting at proximal nodes or floating, 0.3–5 dm.
Culms

erect, 1–4 mm diam., smooth.

erect, decumbent and rooting at nodes, or floating, terete, 1–2 mm diam., smooth.

Cataphylls

1–2, straw-colored to pink, apex acute.

0 or 1–2, straw-colored, apex acute.

Leaves

basal 1–3, cauline 1–2;

auricles 0.6–1.5 mm, apex rounded, scarious;

blade terete to compressed, 0.2–12 cm × 0.5–2 mm.

basal 1–3, cauline 1–4;

auricles 0.8–2.1 mm, apex rounded to acute, membranaceous;

blade terete, 3.7–15 cm × 0.4–1.3 mm, occasionally with filiform, flaccid, and floating leaves to 60 cm.

Inflorescences

panicles of 5–80 heads, 5–25 cm, branches ascending;

primary bract erect;

heads 2–6-flowered, ellipsoid to obovoid, 2–5 mm diam.

terminal racemes of 2–9 heads, 2–10 cm, branches erect;

primary bract erect;

heads 2–12-flowered, obconic or rarely hemispheric, 4–13 mm diam.

Flowers

tepals green to light brown, lanceolate;

outer tepals 1.8–2.5 mm, apex obtuse to nearly acute;

inner tepals 2–2.8 mm, apex obtuse to nearly acute;

stamens 3 or 6, anthers 1/2 filament length.

tepals light brown or greenish to reddish brown, linear to narrowly lanceolate, apex acute to acuminate-subulate;

outer tepals (2.1–)2.8–4.9 mm;

inner tepals (2.1–)2.8–5.5 mm;

stamens 3 or 6, anthers 1/2–3/4 filament length.

Capsules

exserted, chestnut to dark brown, imperfectly 3-locular, obconic, 2.4–3.8 mm, apex acute proximal to beak, valves separating at dehiscence.

usually exserted, dark brown, 1-locular, ovoid to oblong, (3.2–)3.5–6.1 mm, apex acute to acuminate proximal to beak, valves separating at dehiscence.

Seeds

ellipsoid to fusiform, 0.8–1.2 mm, tailed;

body covered with whitish translucent veil.

narrowly obovoid to obovoid, 0.6–0.7 mm, not tailed;

body clear yellow-brown..

n

= ca. 30, ca. 50–60, 2n = ca. 112.

2n

= 80.

Juncus brachycephalus

Juncus supiniformis

Phenology Fruiting summer–early fall. Fruiting mid summer–fall.
Habitat Calcareous marshes, wet meadows, and wetland shores Pond, lake and river shores, marshes, bogs, and ditches
Elevation 100–200 m (300–700 ft) 0–1000 m (0–3300 ft)
Distribution
from FNA
AL; CO; CT; GA; IL; IN; MA; ME; MI; MN; NC; ND; NH; NJ; NY; OH; OK; PA; TN; VA; VT; WI; WV; NB; NS; ON; QC;
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

The northern California and southern Oregon populations (Juncus supiniformis in the strict sense) form long filiform leaves before flowering, are shorter, and have smaller flowers than the northern populations. Except for the filiform leaves, the variation in sizes appears to follow a rough latitudinal cline with the largest plants and largest flowers in Alaska.

Flowers of Juncus supiniformis often form bulbils.

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

Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Septati Juncaceae > Juncus > subg. Septati
Sibling taxa
J. acuminatus, J. acutiflorus, J. acutus, J. alpinoarticulatus, J. anthelatus, J. arcticus, J. articulatus, J. biglumis, J. bolanderi, J. brachycarpus, 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. 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. 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. canadensis var. brachycephalus J. oreganus, J. paucicapitatus
Name authority (Engelmann) Buchenau: Botanische Jahrbucher fur Systematik, Pflanzengeschichte und Pflanzengeographie 12: 268. (1890) Engelmann
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