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Eleocharis geniculata

(L.) Roem. & Schult. (1817)

This name is accepted

Kingdom: Viridiplantae Phylum: Magnoliophyta Class/Clade: Monocots Order: Poales Family: Cyperaceae Genus: Eleocharis

spikerush

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Description

Key Characters:

Growth Form: Annuals.

Stems: Culms densely tufted, pale or green and slightly glaucous, filiform, 7–30 cm tall, 0.2–0.5 mm in diameter.

Roots:

Leaves: Leaves simple. Leaves basal or nearly so, reduced to bladeless sheaths. Margins entire. Sheathing; sheaths pale green, often tinged reddish brown in lower part, 0.5–3 cm long, orifice truncate. Stipules absent.

Flowers: Flowers in spikelets many–flowered, rusty or pale brown, broadly ovoid to ovoid–ellipsoid, 3– 7 mm long, 3–4 mm wide, obtuse; glumes pale brown, membranous, broadly elliptic to ovate, ca. 2 mm long, obtuse, the midnerve green, ending below the glume apex. Flowers bisexual (perfect). Calyx of 6–7 bristles, rusty brown, retrorsely spinulose, slightly longer than the achene. Corolla (petals) absent. Ovary superior; styles base depressed-conical, nearly ⅓ as wide as achene; stigmas 2.

Fruit: Achenes black; glossy; smooth; broadly obovoid; thickly biconvex; ca. 1 mm long. Seeds 1; seed coat thin; free from pericarp; embryo basal; endosperm abundant.

Ploidy: 2n = 10; 20; 30; 38

Habitat: Naturalized in moist ground; marshy places; salt marshes; taro paddies; and seeps.

Elevation Range: 0–760 m.

Historical Distribution

Images

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Synonyms (46)

Bulbostylis capitata (L.) Steven (1817)
Bulbostylis geniculatus (L.) Steven (1817)
Chlorocharis capitata (L.) Rikli (1895)
Chlorocharis geniculata (L.) Rikli (1895)
Cyperus capitatus (L.) Burm.f. ex B.D.Jacks. (1893)
Eleocharis brizantha Steud. (1854)
Eleocharis capitata (L.) R.Br. (1810)
Eleocharis capitata var. dispar (E.J.Hill) Fernald (1906)
Eleocharis capitata var. typica Svenson (1932)
Eleocharis caribaea (Rottb.) S.F.Blake (1918)
Eleocharis caribaea var. achlamydea Zavaro & Pabón (1995)
Eleocharis caribaea var. dispar (E.J.Hill) S.F.Blake (1918)
Eleocharis caribaea var. stokesii F.Br. (1931)
Eleocharis densisquamata Steud. (1855)
Eleocharis dispar E.J.Hill (1882)
Eleocharis geniculata f. brunnea S.González & Reznicek (1996)
Eleocharis geniculata var. minor (Vahl) Roem. & Schult. (1817)
Eleocharis kirkii C.B.Clarke (1902)
Eleocharis melanosperma Steud. (1854)
Eleocharis mexicana Peyr. (1859)
Eleocharis riparia Nees ex Spreng. (1827)
Eleocharis setacea R.Br. (1810)
Eleocharis singularis Steud. (1855)
Eleocharis sintenisii Boeckeler (1888)
Eleocharis valida Boeckeler (1882)
Eleogenus capitatus (L.) Nees (1834)
Eleogenus capitatus var. intermedius Nees (1842)
Eleogenus capitatus var. major Nees (1842)
Eleogenus capitatus var. minor Nees (1842)
Eleogenus capitatus var. recurvus Nees (1842)
Limnochloa constricta (Schrad. ex Kunth) Nees (1842)
Limnochloa densa Liebm. (1850)
Limnochloa geniculata (L.) Nees (1842)
Megadenus capitatus (L.) Raf. (1825)
Scirpus atrofactus Steud. (1855)
Scirpus brownii Spreng. (1824)
Scirpus capitatus L. (1753)
Scirpus caribaeus Rottb. (1773)
Scirpus constrictus Schrad. ex Kunth (1837)
Scirpus depressus Vell. (1829)
Scirpus geniculatus L. (1753)
Scirpus geniculatus var. minor Vahl (1805)
Scirpus interstinctus Poepp. ex C.Presl (1828)
Scirpus repens Willd. (1824)
Scirpus validus (Boeckeler) Kuntze (1891)
Trichophyllum capitatum (L.) House (1920)

Uses and Culture

USES

Natural History

Statewide Status

Naturalized

Island Status

Kaua'i Naturalized
O'ahu Naturalized
Molokai Naturalized
Lana'i Naturalized
Maui Naturalized
Hawai'i Naturalized

Dispersal Agents

Water/Ocean

Pollinators

Bibliography

Name Published In: Syst. Veg., ed. 15 bis 2: 150 (1817)

Other References

Wagner et al. 1990:1402 (K, O, Mo); Oppenheimer 2003:10 (WM); Imada et al. 2008:12 (L); Imada & Kennedy 2020:76 (H)

Occurrences

SNo. Scientific Name Locality Habitat Basis of Record Description Recorded By Record Number Island Source Date
1 Eleocharis geniculata Waimano Trail Moist ground. Preserved_Specimen Kerr, M. Oahu BISH 1945-07-16
2 Eleocharis geniculata W Maui, Lahaina District, Hanakaoo Growing at edge of lawn in wet areas. Preserved_Specimen Oppenheimer, H.L. 40105 Maui BISH 2001-04-04
3 Eleocharis geniculata Makaha Valley ca. 3 mi. down Makaha Ridge Road Pu'u Ka Pele Forest Reserve, perennially dripping cliffs in narrow part of valley with ferns (Blechnum occidentale, Adiantum raddianum, A. capillis-veneris, Pluchea symphytifolia, Erigeron karvinskianus, and Cyrtandra wawrae) Preserved_Specimen Wagner, W.L. 6063 Kauai BISH 1988-04-11
4 Eleocharis geniculata Kawaihau District. Private lands behind Coco Palms, parcel on Makai side of Koki Road. Low depression covered with Bacopa, surrounding by secondary lowland forest of Java Plam and Macaranga tanarius and piles of cut green waste and assorted rubbish. Syzygium cumini, Macaranga tanarius, Megathyrsus maximus, Eclipta prostrata, Leucaena leucocephala, Pluchea indica, P. carolinensis, Amaranthus spinosus, Ipomoea triloba, Solanum torvum, Cyperus spp., Preserved_Specimen Small decicate culms, green throughout, to about 20 cm. tall. Occasional clumps growing out of mud fllats covered in Bacopa monnieri, full to part sun. Seeds black Williams, A.M. 832 Kauai BISH 2023-09-26
5 Eleocharis geniculata Kalaupapa; airport seasonal wetland Preserved_Specimen annual sedge Wysong, M.L. 609 Molokai BISH 2005-02-08
6 Eleocharis geniculata West Maui, Lahaina District, Kahana In muddy ground along gravel rd. Preserved_Specimen Oppenheimer, H.L. 90408 Maui BISH 2004-09-24
7 Eleocharis geniculata W Maui, Lahaina District, Honokahua Growing in lawn. Preserved_Specimen Oppenheimer, H.L. 110152 Maui BISH 2001-11-26
8 Eleocharis geniculata Haena, Hanakoa Valley, W falls, end of main trail seeping vertical basalt; Hedyotis cookiana, H. elatior, Plantago princeps, Deparia cataracticola, Isachne pallens, Asplenium unilaterale, Lipochaeta connata, Selaginella arbuscula, Eragrostis variabilis, Carex meyenii, Machaerina angustifolia, Sphenomeris chinensis Preserved_Specimen erect sedge; leaves dark green; spiklets pale brown Wood, K.R. 12172 Kauai BISH 2006-09-25
9 Eleocharis geniculata Niaupala Fishpond, Kaluaaha Salt marsh. Preserved_Specimen St.John, H. 19956 Molokai BISH 1939-01-02
10 Eleocharis geniculata University of Hawaii, quarry on moist ground Preserved_Specimen Herbst, D.R. 482 Oahu BISH 1967-05-11
11 Eleocharis geniculata On Kahana Valley area along foot trail across the Kahana stream dam, going up more or less parallel to the stream In open grass land, quite common. Preserved_Specimen Scattered in bunches. Herat, T. 138 Oahu BISH 1972-08-13
12 Eleocharis geniculata Makaha Valley, 3 miles down Makaha Ridge Rd In valley bottom in areas of standing water. Preserved_Specimen Flynn, T.W. 1830 Kauai BISH 1986-07-21
13 Eleocharis geniculata Along road to Relay Towers below Mt. Kahili At edge of pool along road. Preserved_Specimen Flynn, T.W. 673 Kauai BISH 1983-12-06
14 Eleocharis geniculata Ninole, Kau In muck of drying freshwater pond next to ocean Preserved_Specimen Degener, O. 35792 Hawaii BISH 1983-05-16
15 Eleocharis geniculata Manele Bay, along coastal trail heading west Soggy seep area along coastal trail. Associated in seep with other wetland plants such as Cyperus involucratus, Echinochloa colona, Kyllinga brevifolia, Paspalum urvillei. Preserved_Specimen Forming thick, bright green low mats. Imada, C. 200716 Lanai BISH 2007-12-09
16 Eleocharis geniculata Rt 450, c.a. 5 km W of 'Ualapu'e Roadside weed from edge of saline, Batis dominated wetland Preserved_Specimen Abundant only in this location where the ground was moister and saline. Hundreds of plants were seen along the road. Strongly clump forming Faccenda, K. 2962 Molokai BISH 2022-12-29
17 Eleocharis geniculata In bog S of the Wailuku River, Hilo Forest Reserve, South Hilo District Within a large bog. Growing with Andropogon, Luzula, Scirpus, and Carex. Preserved_Specimen A frequent sedge. Clarke, G. 601 Hawaii BISH 1981-05-20
18 Eleocharis geniculata Hanalei District, Hanalei Valley, Hanalei National Wildlife Refuge growing in taro paddies Preserved_Specimen Sedge Texeira, A. Kauai BISH 1989-05-09
19 Eleocharis geniculata Kailua, Kawainui Marsh Dike. S end, Mauka side Growing on bank, about 1 foot from waters edge. Associated vegetation- Cyclosorus interruptus, Cyperus polystachyos, Commelina diffusa, Pluchea indica, Cyndon dactylon, Bacopa monnieri, Mimosa pudica. Preserved_Specimen Clumping spike sedge, forming dense mat. Crago, L.M. 2005038 Oahu BISH 2005-02-25
20 Eleocharis geniculata Maunawili trail, near the Pali Hwy where it switches back partly sunny and very wet area Preserved_Specimen Old wooden water storage tank about 15 ft in diameter, growing from crack in wood of tank Faccenda, K. 2227 Oahu BISH 2022-02-05
21 Eleocharis geniculata Kapaa; ditch near coast Preserved_Specimen Degener, O. 2200 Kauai BISH 1926-06-16
22 Eleocharis geniculata Kalalau Trail, along first mile or so Preserved_Specimen Wagner, W.L. 5181 Kauai BISH 1983-12-21
23 Eleocharis geniculata Site 34 OS; Piihonua; Hilo Forest Reserve Dense healthy forest. Associated spp.: Metrosideros polymorpha (pubescent), Ilex anomala, Cheirodendron trigynum, Myrsine lessertiana, Vaccinium calycinum, Styphelia tameiameiae, Rubus hawaiensis, Lycopodium cernum & Cibotium glaucum. Preserved_Specimen Adee, K.T. Hawaii BISH 1979-07-02
24 Eleocharis geniculata Kawai nui Marsh, 50 ft off access road, near the rattle box plants. Near rattle box plants. Preserved_Specimen Preston, D.J. Oahu BISH 1988-08-02
25 Eleocharis geniculata Dry slopes of Koko Crater Preserved_Specimen Herb, 30 cm ht. Christophersen, E. 1299 Oahu BISH 1930-04-06
26 Eleocharis geniculata Halawa Preserved_Specimen Pearsall, G.A. Oahu BISH 1954-03-26
27 Eleocharis geniculata Hilo town, in muddy, standing water at edge of grassy field and paved parking lot, adjacent to Wailoa Stream Preserved_Specimen Oppenheimer, H.L. 41414 Hawaii BISH 2014-04-20
28 Eleocharis geniculata Kalihi Taro patches Preserved_Specimen Forbes, C.N. Oahu BISH 1909-01-01
29 Eleocharis geniculata Milolii Valley Preserved_Specimen Corn, C. Kauai BISH 1984-07-16
30 Eleocharis geniculata Kalihi Taro patches Preserved_Specimen Forbes, C.N. Oahu BISH 1909-06-16
31 Eleocharis geniculata Kalihi Taro patches Preserved_Specimen Forbes, C.N. Oahu BISH 1909-06-16
32 Eleocharis geniculata Milolii Valley Preserved_Specimen Corn, C. Kauai BISH 1984-08-23
33 Eleocharis geniculata Hanalei Dist.; Kalihikai, Power-line Trail Sedge along muddy road. Preserved_Specimen Stone, B.C. 806 Kauai BISH 1955-06-16
34 Eleocharis geniculata Pearl Harbor National Wildlife Refuge, Oahu Growing in wet mudflat, being overgrown by Bacopa monnieri and Pluchea indica. Preserved_Specimen Spiked sedge in round clumps 6-8 inches across. Crago, L.M. 2005070 Oahu BISH 2005-02-23
35 Eleocharis geniculata Waimea; Mana Occasional in marshy places. Preserved_Specimen Hosaka, E.Y. 1667 Kauai BISH 1936-11-05
36 Eleocharis geniculata Hanalei Dist.; Limahuli Valley, secondary forest along stream in valley bottom Along stream in seep on rock outcrop. Area dominated by Psidium, Aleurites & Schefflera w/scattered Metrosideros, Pisonia & Hedyotis. Preserved_Specimen Flynn, T.W. 2320 Kauai BISH 1987-08-20
37 Eleocharis geniculata Hanalei District. Napali Coast State Park, Nualolo Kai, Kalo patch area at base of the complex of Kahua, Spring marshy area surrounded by Coastal Cliff Mixed Shrubland with Leucaena, with Cyperus javanicus, Colocasia esculenta, Cyclosorus, Andropogon, Distaria, Morinda, Pluchea, Lantana, Stachya arvensis, Myoporum, Cocos nucifera, Nicotiana tobacum, Eragrostis variabilis, Chenopodi. Preserved_Specimen In northeast corner of spring area. Forming mats. Blade with red-brown sheath, stem light green becoming dark at base. Spreading from center. Mature achnes shinny black. Tangalin, N. 2117 Kauai BISH 2009-07-11
38 Eleocharis geniculata Ahupuaa of Waimanalo, ili of wawamalu. Growing in grassy area around beach shower in sand/soil mixture. Preserved_Specimen Short turf of Eleocharis with very tiny leaves. Thomas, M.K. 905 Oahu BISH 2024-10-28
39 Eleocharis geniculata Niaupala Fishpond, Kaluaaha Salt marsh. Preserved_Specimen St.John, H. 19951 Molokai BISH 1939-01-02
40 Eleocharis geniculata Crest of Hanalei-Kawaihau Ridge near Kualapa, SW of the Makaleha Mts Uncommon in moist areas & in standing water. Preserved_Specimen Plants stoloniferous; seed mahogany brown; perianth bristles 7. Nagata, K.M. 2085 Kauai BISH 1980-07-31
41 Eleocharis geniculata Kahuku, betw ocean & old air strip On bank of interdune pond. Preserved_Specimen Herb 2-4 in ht. Pearsall, G.A. 472 Oahu BISH 1959-09-22
42 Eleocharis geniculata Pearl City Cultivated potted plant. Preserved_Specimen Purchased from Hui Ku Maoli Ola nursery. Eickhoff, D. Oahu BISH 2009-02-20
43 Eleocharis geniculata James Campbell National Wildlife Refuge, Kahuku, Oahu Growing on a mudflat in a drained pond, soil mesic to wet. Also up on raised area in pond, in drier soil. Growing with Bidens alba, Plantago major. Preserved_Specimen Clumping green, spikes. Crago, L.M. 2005076 Oahu BISH 2005-03-01
44 Eleocharis geniculata Ala Moana Park, west portion near harbor and volleyball courts Mowed, irrigated grass Preserved_Specimen Rhizomatous, locally common only in this area Faccenda, K. 2220 Oahu BISH 2022-02-02
45 Eleocharis geniculata Waipio Peninsula; Waipio, Pouhala Marsh between Kapakahi & Waikele Streams Common sedge in standing water w/Batis & Cyperus laevigatus. Preserved_Specimen Imada, C. 967 Oahu BISH 1996-12-18
46 Eleocharis geniculata Behind PMRF along cane road to Polihale Beach State Park Low, seepy area. Preserved_Specimen Flynn, T.W. 866 Kauai BISH 1984-05-30
47 Eleocharis geniculata Mana Pond, near Barking Sands Edge of pond. Preserved_Specimen Corn, C. Kauai BISH 1977-07-22
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