Flora of North America species comparison

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Juncus bufonius

Juncus subg. Poiophylli

common toad rush, toad rush
Habit Herbs, annual, cespitose, 0.5–4 dm. Herbs, perennial, rarely annual, perennials rhizomatous.
Culms

1–many, occasionally becoming decumbent.

Stems

terete.
Cataphylls

0–2.

Leaves

basal and cauline;

auricles rudimentary or absent;

blade flat, 3–13 cm × 0.3–1.1 mm.

basal and cauline;

blade usually flat, involute, rarely nearly terete, channeled, not septate.
Inflorescences

loose and diffuse or less often compact, usually at least ½1/2 total height of plant;

primary bract shorter than inflorescence.

terminal cymes, usually sympodial (monopodial in J. trifidus);

bracts erect or ascending, flat, involute, or terete;

bracteoles 2, at base of perianth.
Flowers

bracteoles 2;

tepals greenish, lanceolate, 3.8–7(–8.5) mm;

inner series slightly shorter, apex sometimes obtuse;

stamens 3–6, filaments (0.7–)1–1.8 mm, anthers 0.3–0.8 mm;

style 0.1–0.2 mm.

borne singly, not in heads.
Capsules

tan to reddish brown, 3-locular, ellipsoid to narrowly so, slightly truncate, 2.7–4 × 1–1.5 mm, sometimes exceeding inner tepals but usually not outer series.

1-locular (placentae 1/2–3/4 distance to central axis) or 3-locular, rarely beaked.
Seeds

yellowish, widely ellipsoid to ovoid, 0.26–0.49, not tailed.

not tailed (except J. vaseyi).
2n

= 27–37, 58–81, 108–115.

Juncus bufonius

Juncus subg. Poiophylli
Phenology Flowering and fruiting spring–early fall.
Habitat Moist soils in meadows, along lakeshores or stream banks, ditches, or roadsides, especially frequent in drawdown areas, usually in open sites and often becoming weedy
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; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT; Greenland; nearly worldwide
[WildflowerSearch map]
[BONAP county map]
Worldwide
Discussion

Nearly worldwide, Juncus bufonius is found essentially throughout North America except north of the Alaskan and Canadian tTaiga. Juncus bufonius is a highly polymorphic complex that is poorly understood systematically. Insufficient evidence exists upon which to base the segregation of the plethora of taxa that have been recognized out of this group in the past.

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

Species 25 (18 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Plants annual
J. bufonius
1. Plants perennial.
→ 2
2. Leaves minutely serrulate; auricles deeply lacerate
J. trifidus
2. Leaves entire; auricles not lacerate.
→ 3
3. Auricles at summit of leaf sheath 3–6 mm, membranous, transparent; capsules never 3-locular.
→ 4
3. Auricles absent or merely short, scarious or cartilaginous projections less than 2 mm.
→ 5
4. Capsules less than 3/4 length of tepals, borne widely spaced along usually diffuse branches of inflorescence; plants mostly 7–9 dm
J. anthelatus
4. Capsules 3/4 or more length of tepals, borne congested or branch internodes ca. as long as tepals; plants mostly less than 7 dm
J. tenuis
5. Leaf blade channeled to terete.
→ 6
5. Leaf blade flat.
→ 10
6. Inflorescence falsely lateral, overtopped by terete bract that looks to be continuation of culm
J. coriaceus
6. Inflorescence terminal, involucre bract flat or much shorter than inflorescence.
→ 7
7. Perianth segments obtuse
J. squarrosus
7. Perianth segments acute to acuminate.
→ 8
8. Seeds distinctly tailed, tail at least 1/2 length of seed body; capsules golden tan
J. vaseyi
8. Seeds not tailed; capsules chestnut brown or paler.
→ 9
9. Capsules 1-locular or pseudo-3-locular, widely elliptic to rounded, apex rounded; seeds 0.3–0.4 mm
J. dichotomus
9. Capsules 3-locular, elliptic, apex somewhat truncate; seeds 0.48–0.7 mm
J. greenei
10. Capsules chestnust brown or darker; tepals apically obtuse or rounded.
→ 11
10. Capsules tan or light brown; tepals acute to acuminate.
→ 12
11. Anther 1–2 times length of filament, less than 1 mm; capsule usually exceeding perianth
J. compressus
11. Anther 2–4 times length of filament, longer than 1 mm; capsule usually nearly equal to perianth
J. gerardii
12. Capsules 3-locular.
→ 13
12. Capsules 3-locular or pseudo-3-locular.
→ 16
13. Tepals 2.5–3.5 mm; capsule nearly globose.
→ 14
13. Tepals 4–5.5 mm; capsule ellipsoid to narrowly so.
→ 15
14. Tepals green; flowers chiefly arranged along inner side of branches; plants of e North America
J. secundus
14. Tepals usually with brownish midstripe; flowers not secund; plants of w North America
J. confusus
15. Anthers 0.6–0.9 mm; auricles scarious, lobes 0.5 mm; plants of c United States
J. brachyphyllus
15. Anthers 1.2–1.5 mm; auricles scarious to membranous, 0.2–0.3 mm; plants endemic to s Appalachian Piedmont
J. georgianus
16. Auricles 0.5–1(–1.5) mm, membranous
J. occidentalis
16. Auricles 0.1–0.3(–1) mm, scarious to leathery.
→ 17
17. Auricles leathery, yellowish; tepals spreading in fruit, nearly equal to or exceeding capsule; anthers 0.6–1 mm
J. dudleyi
17. Auricles scarious, whitish or sometimes purplish tinged, not leathery; anthers 0.4–0.6 mm.
→ 18
18. Mature capsules light brown or darker; plants of coastal plain of e, se North America
J. dichotomus
18. Mature capsules light tan; plants of interior continent
J. interior
Source FNA vol. 22. FNA vol. 22.
Parent taxa Juncaceae > Juncus > subg. Poiophylli Juncaceae > 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. 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
Subordinate taxa
J. anthelatus, J. brachyphyllus, J. bufonius, J. compressus, J. confusus, J. coriaceus, J. dichotomus, J. dudleyi, J. georgianus, J. gerardii, J. greenei, J. interior, J. occidentalis, J. secundus, J. squarrosus, J. tenuis, J. trifidus, J. vaseyi
Synonyms J. bufonius var. congestus, J. bufonius var. halophilus, J. bufonius var. hybridus, J. bufonius var. occidentalis, J. bufonius var. ranarius, J. congestus, J. ranarius J. section Poiophylli, J. subg. Pseudo-tenageia, J. section Tenageia, J. subg. Tenageia
Name authority Linnaeus: Sp. Pl. 1: 328. (1753) Buchenau: Abhandlungen herausgegeben vom naturwissenschaftlichen Vereine zu Bremen 4: 406. (1875)
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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