Contains 31 accepted taxa overall.
Characteristics
Classification
Citation
JUNCUS Linnaeus, Sp. Pl. 325. 1753.
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TYPE: Juncus acutus Linnaeus Lectotypified by Britton & A. Brown, Ill. Fl. N. U.S., ed. 2. 1: 465. 1913; Hitchcock & M. L. Green, Prop. Brit. Bot. 147. 1930..
Species
| Scientific Name | Common Name | Herbarium Specimens | Status | Photos |
|---|---|---|---|---|
| Juncus acuminatus | Sharp-fruited Rush | |||
| Juncus anthelatus | Large Path Rush, Large Poverty Rush | |||
| Juncus biflorus | Large Grass-leaved Rush | |||
| Juncus brachycarpus | Short-fruited Rush | |||
| Juncus bufonius | Toad Rush | |||
| Juncus canadensis | Canadian Rush | |||
| Juncus coriaceus | Leathery Rush | |||
| Juncus debilis | Weak Rush | |||
| Juncus dichotomus | Forked Rush | |||
| Juncus diffusissimus | Diffuse Rush, Slim-pod Rush | |||
| Juncus dudleyi | Dudley's Rush | |||
| Juncus effusus ssp. solutus | Common Rush, Soft Rush | |||
| Juncus elliottii | Elliott's Rush | |||
| Juncus georgianus | Georgia Rush, Flatrock Rush | |||
| Juncus gymnocarpus | Seep Rush | |||
| Juncus longii | Long’s Rush | |||
| Juncus marginatus | Grass-leaved Rush | |||
| Juncus megacephalus | Large-headed Rush | |||
| Juncus paludosus | Swamp rush | |||
| Juncus pelocarpus | Brown-fruited Rush | |||
| Juncus polycephalos | Many-headed Rush | |||
| Juncus pylaei | Common Rush | |||
| Juncus repens | Creeping Rush | |||
| Juncus roemerianus | Black Needle Rush | |||
| Juncus scirpoides var. compositus | Lobe-headed Rush | |||
| Juncus scirpoides var. scirpoides | Needlepod Rush | |||
| Juncus secundus | Secund Rush, Lop-sided Rush | |||
| Juncus subcaudatus | Somewhat-tailed Rush | |||
| Juncus tenuis | Path Rush, Slender Rush, Poverty Rush | |||
| Juncus trigonocarpus | Redpod Rush | |||
| Juncus validus | Vigorous Rush, Round-headed Rush |
Identification Key
1. Leaf blades absent (only scales or sheaths present), or 1-3, terete and primarily basal; basalmost inflorescence bract solitary, stiffly erect, essentially confluent with the culm and exceeding the inflorescence, the inflorescence appearing lateral
1. Leaf blades present (sometimes 1-3, terete, and basal); basalmost inflorescence bracts 1-many, erect to laxly spreading, shorter to longer than the inflorescence, sometimes the larger bract appearing confluent with the culm, the inflorescence generally appearing terminal
2
2. Leaves not septate (or if septate, most flowers solitary); flowers borne singly or (1)2-12(20) per glomerule or head
2. Leaves septate (incomplete sometimes); flowers 2-60 per glomerule or head
1. (Key A) Leaf blades 1-3 and basal; flowers sessile and 2-6 per glomerule or head; of brackish to marine habitats
1. Leaf blades absent or 1-2 and basal; flowers borne singly, distributed along the inflorescence branches, sometimes pedicellate; of freshwater to slightly brackish habitats
2
2. Leaf blades (0)1(2), usually present on some culms; fruit 3.5-5 mm long, subglobose, 1-locular
2. Leaf blades absent; fruit 1.5-3.2 mm long, trigonous, 3-locular
3
3. Culms densely clumping on the short rhizome; stamens 3; fruit subequal to the tepals, mostly broadly rounded to emarginate
3. Culms solitary along the creeping rhizome; stamens 6; fruit longer than the tepals, usually tapered and apiculate
1. (Key B) Flowers sessile and (1)2-12(20) per glomerule or head
2
1. Flowers borne singly (infrequently in clusters of 2-3), distributed along the inflorescence branches, sometimes pedicellate
5
2. Annual or short-lived perennial; culms submersed, floating, or terrestrial and weak, often repent and mat-forming; leaves often in fascicles; fruit 3.5-5.5 mm long; seeds 0.3-0.4 mm long
2. Perennial; culms mostly erect to ascending; leaves solitary and scattered along the culm; fruit 1.8-2.9 mm long; seeds 0.4-0.7 mm long
3
3. Rhizome internode width (0.8)1.0-1.4(1.9) mm, longest distance between adjacent rhizome cataphylls (5.3)6.3-10.5(13.0) mm; infructescence usually congested, (1.8)2.4-4.7(6.4) cm long
3. Rhizome internode width (0.4)1-3.5(4.5) mm, longest distance between adjacent rhizome cataphylls (0.1)0.4-3(4.6) mm; infructescence usually loose, sometimes congested, (1.4)17.9-103.9(145) cm long
4
4. Tallest culm (27.2)50.8-81.2(100.7) cm, stem base(3.4)5.8–9.6(12) mm wide; sheath of lowest leaf (3.2)4.3-7.8(9.7) cm long; widest leaf blade (2.6)3.1-4.5(5.4) mm wide; anthers (0.5)0.6-1.0(1.3) mm long, exserted
4. Tallest culm (19.2)26.0-44(56.8) cm, base (0.4)2.0-4.4(6) mm wide; sheath of lowest leaf (1.7)2.2-3.8(4.7) cm long; widest leaf blade (1.3)1.6-2.6(3.5) mm wide; anthers (0.2)0.3-0.5(0.7) mm long, concealed by tepals
5. Annual, to 40 cm tall or long; inflorescence length 0.3-0.7 as long as the entire aboveground part of the plant
5. Perennial, 10-100 cm tall; inflorescence length 0.03-0.3 as long as the entire aboveground part of the plant
6
6. Inflorescence diffuse, (2)6-25 cm long, (1)2-15 cm wide; fruit 1.5-3.5 mm long, the apex gradually tapering into a beak; leaf sheath auricle 0.3-1 mm long, membranous
6. Inflorescence relatively compact to somewhat spreading, 1-8(12) cm long, 1-7(9) cm wide; fruit (2.5)2.8-4.7 mm long, the apex rounded, retuse, to abruptly narrow to a beak; auricle 0.2-5 mm long, scarious or membranous
7
7. Auricle at summit of leaf sheath 0.2-0.6(1) mm long, scarious, hyaline-margined; anthers 0.4-0.8 mm long; seed 0.3-0.4 mm long
7. Auricles at summit of leaf sheath 1-3(5) mm long, membranous to subcoriaceous, not hyaline-margined; anthers 0.1-0.2 mm long; seed 0.5-0.7 mm long
1. (Key C) Seeds tailed, 1–2.6 mm long (including tail); seed body covered with whitish translucent veil
2
1. Seeds not tailed, 0.3–0.7 mm; seed body diaphonous yellow-brown
3
2. Heads of 5-50 flowers; fruit subequal to the tepals; seed 1-1.9 mm long
2. Heads of 2-8 flowers; fruit longer than the tepals; seed 1.8-2.6 mm long
3. Heads of (1)2-25(50) flowers, sometimes subglobose; fruit abruptly contracted or sometimes gradually tapering to the beak; cespitose
4
3. Heads of 20-60 flowers, globose to subglobose; fruit tapering to the beak; rhizomatous or cespitose
8
4. Fruit 1.3-2 times as long as tepals
5
4. Fruit subequal to tepals
6
5. Fruit 2.8-4.2 mm long
5. Fruit 4-5.5 mm long
6. Inflorescence with 5-50 heads; tepals 2.6-3.5 mm long, subequal; fruit 2.8-3.5 mm long
6. Inflorescence with 30-250 heads or glomerules; tepals 1.7-2.9 mm long, inner ones shorter; fruit 1.9-2.9 mm long
7
7. Leaf blade with faint ringlike bands at position of septa; roots often with terminal tubers; inner tepals 2.4–2.8 mm
7. Leaf blade with prominent and conspicuous ringlike bands at position of cross partitions; roots without terminal tubers; inner tepals 1.7–2.1 mm
8. Leaf blades laterally flattened or compressed
9
8. Leaf blades terete
10
9. Leaf sheath auricle absent; fruit valve tips remaining united after dehiscence; seeds lance-elliptic, slightly curved and asymmetric
9. Leaf sheath auricle 1-3 mm long; fruit valve tips usually free after dehiscence; seeds broadly elliptic, symmetric
10. Culms 4-8 mm wide near the base, (60)80-150 cm tall; largest leaf blades (24)40-80(108) cm long, 3-7(8) mm wide; inflorescence (10)15-25 cm long, with (15)25-55(80) heads
10. Culms 1-3 mm wide near the base; largest leaf blades 2-24 cm long, 1–2 mm wide; inflorescence 1-10 cm long, with 1-23(32) heads
11
11. Basal leaf sheaths and cataphylls usually reddish; uppermost leaf blade often shorter than the sheath; heads strictly globose; tepals reddish brown to purplish, the inner ones shorter
11. Basal leaf sheaths and cataphylls primarily straw-colored to brown; uppermost leaf blade often longer than the sheath; heads usually somewhat lobed; tepals green to light brown, subequal
Genus Synonyms
| Synonym | Full Citation | Basionym | Type |
|---|---|---|---|
| No synonyms found. | |||