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Xyris complanata

R.Br. (1810)

This name is accepted

Kingdom: Viridiplantae Phylum: Magnoliophyta Class/Clade: Monocots Order: Poales Family: Xyridaceae Genus: Xyris

yellow-eyed grass

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Description

Key Characters:

Growth Form: Perennial herbs, solitary or in small clumps.

Stems: Rhizomes.

Roots: Fibrous root system.

Leaves: Leaves simple. Alternate, equitant. Blades linear often falcate, somewhat rigid, twisted, 10–30(–50) cm long, 1.5–4(–6) mm wide. Apex acuminate. Base dilated near base. Surfaces glabrous. Margins minutely scabrous. Veins parallel. Sheathing, sheaths open. Stipules absent.

Flowers: Flowers on terminal scapes 1–6 dm long, twisted and compressed, with scabrous ribs, spikes oblong–ovoid to cylindrical, 5–25 mm long, 4–8 mm in diameter, lower bracts subtending each flower broadly elliptic, 2–4 mm long, upper ones 5–6 mm long; lateral. Flowers odorless and without nectar, pollinated by pollen–gathering bees, bisexual (perfect). Calyx zygomorphic; sepals unequal, the middle one larger, hood-like, caducous, the lateral ones boat-shaped to spatulate, margins often ciliate; ; sepals 4–5 mm long, keel narrow, fimbriate above middle. Corolla of 3 petals, yellow, 5–6 mm long. Stamens 3(6), opposite the petals; filaments adnate to petals; anthers opening by longitudinal slits. Ovary superior, 3-carpellate; ovules orthotropous. style terminal, unlobed or 3-lobed.

Fruit: Capsules ovoid; 3–3.5 mm. Seeds ovoid to ellipsoid; ca. 0.4 mm.

Ploidy: 2n = 26; 52

Habitat: Cultivated for use in flower arrangements at least in Hilo and sold as 'ahaniu; now at least sparingly naturalized in wet muddy areas and on lava; in the vicinity of Mountain View and Glenwood; Hawai'i;.

Elevation Range: ca. 500 m.

Historical Distribution

Images

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Uses and Culture

USES

Natural History

Statewide Status

Naturalized

Island Status

Kaua'i Naturalized
Hawai'i Naturalized

Dispersal Agents

Water/Ocean

Pollinators

Bibliography

Name Published In: Prodr. Fl. Nov. Holland.: 256 (1810)

Other References

Wagner et al. 1990:1615 (K, H); Faccenda, Arthur, et al. 2025:220 (KEY)

Occurrences

SNo. Scientific Name Locality Habitat Basis of Record Description Recorded By Record Number Island Source Date
1 Xyris complanata Alakai Swamp, Sincock bog # 4, USGS bog, not fenced, near old cabin site. Metrosideros -- Oreobolus furcata open bog. With Cheirodendron platphylla, Leptecophylla tameiameiae, Dicranopteris linearis, Carex montis -eeka, Rhynchospora spicaeformis, Coprosma elliptica. Preserved_Specimen weedy plants 1-2 ft ht with yellow flowers. Perlman, S. 23684 Kauai BISH 2013-09-03
2 Xyris complanata South Hilo District, Waiakea. Buffer zone collections along Stainback Highway Preserved_Specimen Funk, E.J. Hawaii BISH 1998-12-15
3 Xyris complanata Ihope Rd., Mt. View Preserved_Specimen Flowers yellow. Stemmermann, R.L. 6675 Hawaii BISH 1980-06-30
4 Xyris complanata Mohihi Bog, inside fence. Montane wet bog dominated by Metrosideros, Rhynchospora and Oreobolus with Drosera, Lobelia, Styphelia, Vaccinium and Deschampsia. Preserved_Specimen Perennial clumping herb with linear leaves; only one plant seen in bog that was subsequently pulled. Wysong, M.L. 946 Kauai BISH 2008-01-09
5 Xyris complanata South Hilo District, Waiakea. Collected along Stainback Highway corridor Preserved_Specimen Funk, E.J. Hawaii BISH 1999-04-23
6 Xyris complanata Na-Pali Kona Forest Reserve, Lehuamakanoe bog along trail from Alakai Picnic Area to Alakai Swamp trail metrosideros-Rhynchospora open bog. W. Deschampsia, Dichanthelium, Drosera, Vaccinium reticulatum, Cibotium. Occasional in bog. Preserved_Specimen Herb, clumping, leaves and scapes green, petals yellow. Wood, K.R. 14313 Kauai BISH 2010-09-14
7 Xyris complanata Waimea district, Kokee state park, along Alakai swamp trail, at Lehua Makinoe. Open bog with Metrosideros shrubs. Metrosideros spp., Vaccinium, Dicranopteris, Oreobolus sedge, grasses and Drosera. Preserved_Specimen Perennial herb forming dense clumps, base of leaf sheaths purple-pink. Inflorescences. to 50 cm tall, bracts grayish brown, corolla with 3 yellow petals. Localized in several areas but spreading and invasive Lorence, D.H. 10201 Kauai BISH 2010-06-15
8 Xyris complanata Puna District, Hawaii Volcanoes National Park, near Napau Crater Trailside in open area with Andropogon, Dicranopteris and Machaerina. Preserved_Specimen Herb ca. 1 ft tall. Flowers yellow. Cuddihy, L.W. 1615 Hawaii BISH 1983-11-23
9 Xyris complanata Border of Waimea & Hanalei Districts: Halehaha bogs Metrosideros mixed bogs w/ Dichanthelium spp, Oreobolus, Lysimachia daphnoides, Carex spp, Rhynchospora, Vaccinium, Gahnia, Astelia waialealae, Geranium kauaiense, Viola. Preserved_Specimen Collected near rain gauge, corolla yellow. Wood, K.R. 3415 Kauai BISH 1994-08-12
10 Xyris complanata S Hilo District, Upper Waiakea Forest Reserve Occasional in wet places; disturbed ohia woods along highway. Preserved_Specimen Flowers yellow. Webster, G.L. 14026 Hawaii BISH 1968-07-02
11 Xyris complanata Kealia Forest Reserve, Makaleha Mtns. Transect #2A from S of Malamalama Peak to S of Leleiwi Peak Low, open marshy wet shrubland and bogland with Metrosideros polymorpha, Antidesma platyphyllum, Dicranopteris linearis, heavily damaged by Hurricane Iniki and invaded by Clidemia, Melastoma, Psidium cattleianum, & Lantana camara. Preserved_Specimen Perennial herb forming dense clumps in marshy ground. Corolla bright yellow, fugacious. Lorence, D.H. 7366 Kauai BISH 1993-04-16
12 Xyris complanata Summit of Namolokama, rolling hills with bogs, stream drainages, and steep perimeter rim, Metrosideros windswept shrubland few canopy trees of Cheirodendron & Metrosideros -w/ Dubautia laxa, D. plaeata, Melicope clusiifolia, M. waialealae, M. kavaiensis, M. wawraeana, M. cruciata, Dicranopteris linearis, Sticherus owhy Preserved_Specimen herb, small clumps occasional in bogs Wood, K.R. 8169 Kauai BISH 2000-02-01
13 Xyris complanata Kawaihau-Hanalei District Boundary, along the Power Line Trail, vicinity of summer camp (near Mt. Kualapa) Rain forest with Metrosideros spp. dominant, also Antidesma, Syzygium, invaded by strawberry guava, clearings with Dicranopteris. Common, naturalized along roadise and in boggy areas. Preserved_Specimen Perennial herb, stems densely clustered. Inflorescence erect, corolla light yellow. Lorence, D.H. 6378 Kauai BISH 1989-10-07
14 Xyris complanata Hanalei District Alakai swamp trail, about 1 mi in, in Lehua Makanoe bog; Metrosideros - Dicranopteris linearis wet forest; w/Cheirodendron spp., Scaevola procera, Bobea brevipes, Dodonaea viscosa, Ilex anomala, Coprosma kauaensis, Nestegis sandwicensis, Leptecophylla tameiameiae, Psychotria greenwelliae, Santalum f.v. Preserved_Specimen many plants about 2 ft ht with flowers & fruit; flower color yellow Perlman, S. 23494 Kauai BISH 2013-05-31
15 Xyris complanata 1 mi SE of Mountain View in Hawaiian Acres Broken, not very rough aa lava. Preserved_Specimen Common on lava surface in grass, moist in low places. Leaves twisted, flowers bright yellow, 3 petals spreading horizontally. Fosberg, F.R. 44473 Hawaii BISH 1963-11-25
16 Xyris complanata Stainback Hwy near N Kulani Rd. Junction Common along roadside in edge of deep grass. Preserved_Specimen Single stems or several, erect, flowers bright yellow. Fosberg, F.R. 60549 Hawaii BISH 1980-09-06
17 Xyris complanata Stainback Highway, South Hilo District Roadside plant in disturbed Metrosideros closed forest. Preserved_Specimen Height 2 1/2 to 3'. Flowers yellow. Clarke, G. 237 Hawaii BISH 1979-07-11
18 Xyris complanata Waiakahiula, Kaohe Ahupuaa, SE slope of Kilauea, SE from 4 Road and Anthurium Street toward Kaimu. Transect 42, Station 18. Wet ohia forest with other native trees and a treefern and native shrub understory. Unshaded. Preserved_Specimen Herb. Jacobi, J.D. 1308 Hawaii BISH 1979-05-23
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