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Acacia mearnsii

De Wild. (1925)

This name is accepted

Kingdom: Viridiplantae Phylum: Magnoliophyta Class/Clade: Eudicot-Rosids Order: Fabales Family: Fabaceae Genus: Acacia

black wattle

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Description

Key Characters:

Growth Form: Trees (shrubby when young) up to 50 m tall.

Stems: Branches densely minutely gray pubescent.

Roots:

Leaves: Leaves compound (bipinnate). Alternate. Blades with 8–21 pairs of pinnae, leaflets 20–33 pairs in the lower pinnae, up to 40 pairs in the uppermost pinnae. Leaflets linear–oblong. 1.5–4 mm long, 0.5–0.8 mm wide, with a nectary on the main rachis between or near each pair of pinnae. Petiolate.

Flowers: Flowers bracteoles absent, flowers ca. 1.8 mm long, in heads ca. 5 mm in diameter (excl. stamens), these arranged in terminal leafy panicles not exceeding the subtending leaves. Flowers mimosaceous. Calyx campanulate. Corolla dark yellow. Stamens numerous, ca. 3 mm long. Ovary superior.

Fruit: Pods oblong; somewhat moniliform; laterally flattened; constricted between all of the seeds; 7.5–10 cm long; 0.6–0.8 cm wide; sutures gray; pubescent. Seeds ellipsoid; laterally flattened; 4–7 mm long; 3–6 mm in diameter.

Ploidy: 2n = 26

Habitat: Pastures and dry to mesic forest.

Elevation Range: 245–1,220 m.

Historical Distribution

Images

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Uses and Culture

USES

  • Yes

Natural History

Statewide Status

Naturalized

Island Status

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

Dispersal Agents

Water/Ocean
Forestry

Pollinators

Notes

  • Description digitized by Tiffany Flood
  • Description digitized from the Manual of the Flowering Plants of Hawaii

Bibliography

Name Published In: Pl. Bequaert. 3: 61 (1925)

Other References

Wagner et al. 1990:642 (K, O, L, M, H); Hughes 1995:5 (Mo); Starr et al. 2006:35 (Ka)

Occurrences

SNo. Scientific Name Locality Habitat Basis of Record Description Recorded By Record Number Island Source Date
1 Acacia mearnsii Waimea, road to Alakai Swamp Preserved_Specimen fallen tree 20'; green fruit, cream flowers Chock, A.K. 401 Kauai BISH 1952-02-06
2 Acacia mearnsii Palikea Preserved_Specimen Pearsall, G.A. Oahu BISH 1954-06-11
3 Acacia mearnsii Olinda Preserved_Specimen Degener, O. 89111 Maui BISH 1952-03-26
4 Acacia mearnsii Lalakoa Preserved_Specimen Munro, G.C. 313 Lanai BISH 1928-04-17
5 Acacia mearnsii Makiki-Tantalus trail Preserved_Specimen Garber, D.W. 375 Oahu BISH 1920-04-18
6 Acacia mearnsii Haleakala, Park resources Management Office area, behind glass greenhouse Preserved_Specimen Parry, R. Maui BISH 1997-03-12
7 Acacia mearnsii East Maui, Haleakala Preserved_Specimen Andrews, Mrs. Maui BISH 1968-02-14
8 Acacia mearnsii Keekeehia, Ulupalakua, Moo Muku dry pasture land, by the side of the road Preserved_Specimen tree 5m x 2dm. Crown 4 m wide Woolford, H.A. 92 Maui BISH 1955-12-22
9 Acacia mearnsii Kapalama Valley, Koolau Range dry upper forest Preserved_Specimen tree; 3-4 m or higher Tongg, R. 52 Oahu BISH 1942-11-01
10 Acacia mearnsii Road system between Ka'ena and Kealia trail Dry disturbed forest Preserved_Specimen Abundant. Well naturalized Faccenda, K. 2151 Oahu BISH 2021-11-06
11 Acacia mearnsii Kapalama Valley, Koolau Range dry upper forest Preserved_Specimen tree; 3.5 m Kuykendall, J.R. 47 Oahu BISH 1942-11-01
12 Acacia mearnsii K2, Kahoolawe Restoration/planting site. Substrate: hard pan. Vegetation: Sesuvium portulacastrum. Preserved_Specimen Tree; .5 meter sapling (1). No flowers or fruit. Starr, F. 412272 Kahoolawe BISH 2004-12-27
13 Acacia mearnsii 4.5 miles up Molokai Forest Road, W side of road. Kalamaula Game Mangament Area Lowland mesic forest. Preserved_Specimen Tree with woody stem; lvs bipinnately compound; corolla dark yellow. Occasional. Hughes, G.D. Molokai BISH 1991-08-19
14 Acacia mearnsii Waimea, Kokee State Park, along Kokee-Halemanu Trail, from Camp Sloggett to Halemanu Valley mixed mesophytic forest of Acacia koa and Metrosideros, along ridgetop Preserved_Specimen Tree 4-6 m. Flowers pale yellow, fragrant. Fruit green Lorence, D.H. 5805 Kauai BISH 1988-02-17
15 Acacia mearnsii Keekeehia, Ulupalakua, Moo Muku dry pasture land, by the side of the road Preserved_Specimen tree 5m x 2dm. Crown 4 m wide Woolford, H.A. 92 Maui BISH 1955-12-22
16 Acacia mearnsii Na Pali-Kona Forest Rserve, Unit D; 2km E of Kalalau Lookout Mesic forest. Preserved_Specimen Tree to 4m; stamens pale yellow. Annable, C.R. 3197 Kauai BISH 1996-12-17
17 Acacia mearnsii Kuaokala Trail, Kuaokala Forest Reserve. Area overlooking Makua Valley. Along ridgeline trail. Growing out of scabrous eroded rocky soil. At an area along the trail where Metrosideros polymorpha began to occur. With M. polymorpha, Odontosoria, Pinus (see BISH 788121), and Stachytarpheta. Preserved_Specimen 4-5 m tall shrubby tree. Trees are present throughout Forest Reserve (some up to 30 m tall). Flowers globose, pale yellow, faintly sweet smelling. Grayish-brown bark smoothish with tiny fissures. Some trees exuding sap. Walvoord, N. 2023023 Oahu BISH 2023-08-13
18 Acacia mearnsii Kakalahale Game Mangament Area Lowland mesic shrubland. Preserved_Specimen Erect tree 3-8 m high; trunk 3-4 diam. and woody; lvs bipinnately compound; flwr w/yellow corolla; constriction between seeds in the pods. Occasionally found. Hughes, G.D. Molokai BISH 1990-12-07
19 Acacia mearnsii Kamokou Preserve, Kupai`a Gulch, East Moloka`i. Gulch in mintane Metrosideros/native shrubland. Preserved_Specimen Tree with yellow flowers and green pods. Pratt, L.W. 1227 Molokai BISH 1982-05-29
20 Acacia mearnsii East Maui, Ulupalakua, adjacent to Tedeschi Winery, NW of Puu Mahoe Open mesic slope, forming open overstory with Schinus terebinthifolius; understory of Bryophyllum pinnatum or bare soil. Preserved_Specimen Tree 20 ft. tall; no flowering noted, only occasional fruiting. Imada, C. 200222 Maui BISH 2002-07-16
21 Acacia mearnsii Highway 11, 47 - 48 mile marker, Kau District, along roadside Roadside. Preserved_Specimen Bio, K.F. 1004001 Hawaii BISH 2001-06-04
22 Acacia mearnsii East Maui, 100' E of jct. of Hwy.337 and Haleakala Hwy Preserved_Specimen trees 50', grey bark; lemmon-yellow flowers Henrickson, J.S. Maui BISH 1969-07-13
23 Acacia mearnsii along Highway 37 near Kula San Preserved_Specimen Tree ~30' with somewhat rough, blackish bark, dark green leaves, and pale yellow flowers Herbst, D.R. 782 Maui BISH 1967-12-15
24 Acacia mearnsii Waimea Preserved_Specimen small tree 25', 8 diam. Little Jr., E.L. 31076 Hawaii BISH 1976-08-18
25 Acacia mearnsii Road to Kumuwela Lookout Preserved_Specimen tree 30-40'. Flowers white Crosby, M.R. 1495 Kauai BISH 1964-06-19
26 Acacia mearnsii Waianae Range, ridge south of Palikea Preserved_Specimen small tree, ~12 ft. Wilbur, R.L. 541 Oahu BISH 1948-03-26
27 Acacia mearnsii 10 mi SE of Pukalani Preserved_Specimen tree 40', 10 diam. Little Jr., E.L. 31092 Maui BISH 1976-08-24
28 Acacia mearnsii Kokee HUMAN_OBSERVATION Friday, J.B. Kauai 10/10/2013
29 Acacia mearnsii Waimea HUMAN_OBSERVATION Friday, J.B. Hawaii 11/8/2010
30 Acacia mearnsii Near Kokee Preserved_Specimen large tree Degener, O. Kauai BISH 1950-02-09
31 Acacia mearnsii Kokee HUMAN_OBSERVATION Friday, J.B. Kauai 10/10/2013
32 Acacia mearnsii Hilo Preserved_Specimen Hawaii BISH 1939-05-10
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